Ceramic Coating of Automotive Components

The components in an automobile engine are often made from a range of different materials. The variations in the metallurgical properties of these materials can cause mechanical parts to absorb or disperse heat at different phases in the engine cycle. Regulating these temperature fluctuations among both internal and external engine parts can improve horsepower and performance characteristics, leading to more efficient vehicle operation.

Ceramic coatings are increasingly used to provide protection between different engine parts, helping to increase wear resistance, reduce friction, and improve heat shielding. These factors have a significant influence on horsepower ratings, and augmenting them through ceramic coating can often enhance an automobile’s performance. In addition, these coatings enable metal components to interact in a more uniform and compatible fashion.

Applying a Ceramic Coating

Before a ceramic coating is applied to an automotive component, the component’s surface is typically treated with a smoothing agent or sandblasting in order to remove the uneven outer surface and any contaminants that may have accumulated. After the clean bottom layer is revealed, the part is often heated in an oven to reduce its molecular porosity. Without this treatment, any contaminants remaining after the initial stage may be brought to the surface, forcing the coating layer to detach from the substrate.

Common automotive ceramic coatings, such as titanium and tungsten, are usually applied with a gravity-fed spray gun. The gun’s nozzle tends to be narrow to provide precise application control. Solvent coatings are typically sprayed at lower pressure, while liquid-based coatings are sprayed at higher pressure, but in both cases the process occurs inside a spraying booth. During spraying, it is important to keep careful control over the ceramic layer’s thickness, as the coating must be very thin and evenly distributed in order to keep it from running.

Inspection and Curing

Once the coating stage is complete, the component is examined to evaluate the uniformity of the ceramic film distribution. It is then air dried to allow the evaporation process to occur, and placed in an air-circulation curing oven that will provide an even heating treatment. Curing is performed at incrementally rising heat to address temperature transition phases, and most processes begin at roughly 175 degrees Fahrenheit before rising to a maximum of 600 degrees. The component is often burnished to achieve a more precise thickness level and to ensure it meets clearance requirements. Depending on the part, additional finishing treatments, such as vibration polishing, can be performed.

Automotive Applications

Two of the most common applications for automotive ceramic coatings involve exhaust manifolds and headers. A ceramic coating applied to a manifold or header will provide increased resistance to corrosion, such as rust, and lower the rate of heat loss, resulting in greater power output. When applied to internal headers, these coatings increase the speed of the exhaust gas and reduce overall turbulence by providing a smoother surface. Some other automotive components commonly coated with ceramics include:

Cylinder Heads: Applying a ceramic coating to a combustion chamber’s cylinder head and exhaust ports helps circulate exhaust gas at a faster pace while providing a more intense burn in the chamber. This coating can also improve thermal transfer between the gas and the cylinder head, and an additional heat dispersal coating can help cool the head.

Pistons: A piston can be made more efficient with a ceramic coating, which improves the device’s heat reflection and transfers part of the detonation energy into the fuel burning phase. This can result in higher fuel burning efficiency and reduced carbon accumulation, which in turn makes detonation more effective.

Piston Skirts: Coated piston skirts provide a dry sliding surface for engine startup, and feature increased resistance to abrasion and scratching while moving within the engine block. A ceramic coating can also be layered on the piston ring to reduce friction and enhance wear resistance between the ring and the cylinder’s inner surface.

Intake Manifolds: An intake manifold with an interior ceramic coating exhibits a lower level of heat penetration and a cooler mixture of air and fuel. Applying an oil dispersing coating to the bottom of the manifold can also lower heat transfer between the oil and the intake.

Ceramic coatings are often available in specific formulations designed to focus on thermal resistance, friction reduction, corrosion resistance, or oil shedding. These specialized coatings can be used to deliver a particular material characteristic without compromising the rest of the component’s properties.

Coating Procedure For Plastisol Coatings

Plastisol coatings are applied to many different products in order to supply them with aesthetic qualities, tactile softness and gripping power. For instance, tools like pliers and screwdrivers are often fitted with plastisol coatings on their handles in order to provide the user with a solid grip instead of sheer metal. Plastisol coatings involve a plasticized resin combined with many PVC particles, which provide the plastisol with increased durability, toughness and thickness. In order to stay affixed to substrates, plastisol must be combined with a primer, which connects the plastisol particles to the substrate. Different kinds of primers are used depending on the adhesion coating method and the intended result. The plastisol itself has many desirable features, including chemical resistance to acids, alkalines, detergents, oils and certain solvents. Plastisol coatings also maintain structural integrity to - 65 degrees Fahrenheit and provide extraction resistance to different oils and detergents. A plastisol coating can perform well for approximately ten years. Plastisol mixtures can be varied to allow differences in gloss, thickness, toughness and other physical properties.

There are many types of coating procedures that work well with plastisols, most all of which involve heating (curing) the substrate and plastisol resin and a cooling period. These different plastisol coating procedures yield a variety of results and differences in the thickness, texture and geometry of the coating. Some coatings are directly applied to a substrate while others are made in molds. Dip Molding

Dip molding is accomplished in either a hot or cold dip process. In hot dip molding, the substrate is heated and the plastisol resin is heated until bubbles appear, as if it were boiling. The substrate is then slowly dipped straight into the liquid plastisol and then removed slightly faster so the entire piece is coated in plastisol. Cold dip molding is used when the substrate cannot undergo heating, such as in the case of a wooden or fabric substrate, and it is simply dipped into the heated plastisol resin as is. After the dipping procedure, both hot and cold dip molding require the substrate be briefly “cured,” or heated until the plastisol achieves a solid state. Slush Molding

Slush molding is similar to dip molding but involves an extra step to ensure complete coating of a substrate. The process is generally used in cases where the substrate has a complex geometry and includes nooks and crannies that may be difficult to coat by simply dipping the piece into the plastisol resin. Following the dipping procedure, a substrate undergoes slush molding by being affixed into a centrifuge that spins very quickly. This spinning process ensures that the resin fills in all the parts of the substrate. The substrate is then cured and the resin solidifies as in dip molding. Rotational Molding

Rotational molding is used to make products that are hollow, such as buoys and balls. A mold of the product is filled with heated resin, and then the mold rotates at slow speed, allowing the liquid within to slowly coat the entirety of the mold. The plastisol eventually solidifies in the shape of the mold. Casting

Casting is similar to rotational molding but does not involve the movement. When a product with a complex geometry needs to be coating in plastisol, a mold can be made of the shape of plastisol needed. The heated plastisol liquid is then poured into the mold and heated until it solidifies. Once it solidifies, the plastisol mold acts as a sleeve for the product, and can be affixed to the substrate with a small amount of adhesive. Spray Coating

Spray coating is used to apply a very thin film coating of plastisol to a substrate. The substrate is sprayed with heated liquid plastisol by a gun, and then heated to allow the plastisol to solidify. Screen Printing

Screen printing is accomplished when liquid plastisol is used as an ink to coat paper or fabric in very specific designs as determined by a die. The die is dipped into the liquid plastisol, which is then pressed into the substrate.

Fusion Bonded Epoxy

Epoxy is an extraordinarily versatile coating with applications ranging from the automotive industry to do-it-yourself at home projects. Both waterborne and powder based epoxies are employed because of their high level of adhesion, and resistance to corrosion and heat—they can be clear or opaque, and with additives can easily be manipulate to resemble a variety of other materials, such as finished concrete or granite. Fusion bonded epoxy coating (FBE), a powder-based coating, possesses the same properties as traditional epoxy and is used to coat and protect steel pipeline, piping connections, and valves. It earns its name “fusion bonding” from the process by which it adheres to a substrate—when the hardener and epoxy react and the coating takes solid form, the chemicals involved are cross-linked—the process is irreversible, even with severe heat applications.

Fusion Bonded Epoxy Components

What enables chemical cross-linking, and makes FBE such a strong coating, is a combination of four separate components: resin, hardener, fillers, and color pigments. Resin and hardener comprise the adhesive element of FBE, and are often referred to as the “binder.” The epoxy resin, also known as “oxirane” is comprised of resin molecules that each carry one oxygen atom and two carbon atoms, which are highly reactive. When mixed with hardener, the resin and hardener react and adhere to the substrate.

The hardener itself is what determines many qualities of the final fusion bonded epoxy mix, such as flexibility and chemical resistance. The addition of fillers and pigment can alter properties such as hardness, thickness, permeability, and color. Resin, hardener, fillers, and pigment are usually solid in form.

How FBE Powder is Manufactured

After all four components are mixed and blended, the resulting dry mixture enters an extruder, where the mixture is compressed, heated, and melted until semi-liquid. The temperature of the extruder barrel is kept between 50-100 degrees C so as not to significantly alter the chemical properties of the ingredients while they are evenly mixed together. The mixture is then extruded and passed between rollers until it forms a solid sheet. The sheet is then cut into tiny pieces, which are then ground up into powder. The final powder mixture is then packaged.

Applying Fusion Bonded Epoxy Coating

Fusion bonded epoxy coating application takes place in three general stages. First, the metal surface or substrate must be cleaned. After adequate cleaning, the metal should be heated to the appropriate temperature for FBE powder application (because heat is needed in order for the powder to assume liquid form and adhere). The last stage involves properly applying the FBE powder.

To properly clean the metal, blast cleaning is commonly used. Because dust and rust and other grit and grime can inhibit proper coating adhesion, blast cleaning effectively removes such build-up, making the surface rough and clean. In order to remove oil and grease, a solvent cleaning agent may be used.

After the metal has been sufficiently cleaned, it must be heated. Induction heating, which requires that the metal be exposed to alternating electric currents, is a common method; other common choices are oven heating and infra-red heating. Once the metal is heated, the coating process can begin. The epoxy power is applied with an electrostatic spray gun—the powder is literally ionized and charged, so as to adhere to the metal—and as the molten powder meets the metal it forms a strong, irreversible bond. After the powder sits for a few seconds, it assumes solid form.

The application process is quick, produces limited amounts of waste, and enables quick and smooth production. Since the coating dries quickly, the end products are able to be moved shortly after the process ends.

General Industrial Paint Componesnts

Industrial paint, as used to protect metal, wood, and a wide range of other materials, possesses a variety of traits that can be manipulated to provide application-specific coverage. Of course, these characteristics depend in a large part upon the ingredients of the paint and the performance specifications of the selected application. Application methods, too, can influence the quality of the paint coverage and determine how well paint adheres to the substrate. Typically, there are four main components in a paint: pigment, binder, liquid, and additives. Application methods depend on the particular paint, but can include spray application, brush methods, and electrostatic spraying.

Pigment

A paint’s pigment plays a large role in determining color and appearance. Some pigments also provide added bulk, helping to thicken a paint when needed. In its unmixed form, a pigment is simply a powder. There are two general categories of pigments: prime and extender.

Prime Pigments

Prime pigments are mainly responsible for color or whiteness in a paint, as well as the paint’s ability to hide undesirable surface flaws. In paints that exhibit a white hue, titanium dioxide is the main ingredient. In paints the express other colors, the pigments are selected to absorb only certain kinds of light, thus yielding a given color. Organic pigments yield the brightest colors, while inorganic pigments yield less bright but more durable colors.

Extender Pigments

Extender pigments are designed to add bulk, but are not as well-suited to hiding surface flaws as prime pigments. They do, however, influence the paint’s overall sheen, color retention, and abrasion resistance. Silica and silicates, for example, are extender pigments that increase the paint’s durability. Zinc oxide helps prevent mildew and corrosion, and is especially useful in outdoor applications.

Binder

In a paint mixture, the binder is responsible for providing adhesion, binding the pigment, and also gives the paint resistance properties which make the final coating tough and durable. The binder itself is clear and glossy, but the presence of pigment interferes with this quality. Depending on the ratio of pigment to binder, or the PVC (pigment volume concentration) the paint can assume varying levels of glossy finish. Paints with the glossiest finish often have a typical PVC of 15 percent, while the most matte paints have a PVC anywhere from 40 to 80 percent. Paints with less gloss have more binder per unit of pigment, and tend to be more durable. There are two specific types of binder: oil-based and latex-based.

Oil-Based Binder

Oil-based paint requires a binder that has similar properties to the paint—in this case, the binder oxidizes or dries when exposed to air, hardening along with the rest of the paint. Once applied, the liquid factor of an oil-based paint evaporates, and the binder then reacts with the air to harden into place with the pigment. However, sometimes this process can result in over-dry, brittle paint, and chipping can occur. Additionally, the oxidation makes the paint prone to yellowing.

Latex-Based Binder

Latex-based paints actually do not possess latex—rather, the binder that is used (plastic-like in nature) creates a film in the paint that resembles natural latex rubber. Almost all water-based paints have a latex-based binder. When the coating is applied, water evaporates from the paint, leaving behind a film of pigment and latex-based binder, which bind together into one continuous coating. The process by which the binder and pigment are fused is called coalescence. However, because the binding agent is thermoplastic, it cannot be applied at too low a temperature or the binder will be too hard and difficulty will arise during fusing. Common types of latex-based binder include acrylic and vinyl acrylic.

Liquid

In the most basic sense, the liquid component of a paint is simply responsible for transporting the binder and pigment to the substrate surface. The type of liquid depends upon the other components of the given paint. Oil-based paints, for example, can use a basic paint thinner as the primary liquid. Latex-based paints, on the other hand, tend to use water as their liquid.

Additives

When certain properties need to be manipulated or enhanced, additives are often the solution. Thickeners, for example, are additives that help thicken the paint to make application easier. Surfactants help disperse pigments within the paint, ensuring the coat is even and stays in place. Co-solvents help the binder film formation and help prevent paint damage from occurring if the pain is frozen. Co-solvents also make application easier by lengthening the amount of time the paint can be open before beginning to set.

The History Of Green Chemistry and Processes

What is Green Chemistry?

The term “green chemistry,” also known as clean chemistry or benign and sustainable chemistry, refers to the design of chemicals and formulation of processes that reduce the risk to humans and minimize environment pollution. The goal of green chemistry solutions is to lessen or eliminate hazardous impacts of chemicals over a chemical product’s life-cycle. Key guidelines associated with green chemistry are outlined in the Environmental Protection Agency’s “Twelve Principles of Green Chemistry,” which serves as the basis of creating and implementing chemicals and processes.

A Brief History of Green Chemistry

Green chemistry traces back several decades and can be linked to impactful environmental activists, such as Rachel Carson. Her 1962 publication, “Silent Spring,” helped direct the public’s awareness to pesticides and their ties to environmental pollution. Less than a decade later, The Environmental Protection Agency (EPA) was formed in 1970. The EPA references its existence as the extended shadow of Rachel Carlson who is considered a leading innovator of environmental protection, a cause that has paved the way to current green chemistry practices.

President Richard Nixon’s efforts for environmental sustainability lead to the creation of the Citizen’s Advisory Committee on Environmental Quality and a Cabinet-level Environmental Quality Council in 1969. In his speech announcing the creation of the council, Nixon urged the new council and the committee “…to examine the full range of variables which affect environmental quality.” Nixon’s efforts were criticized for not being forceful enough. Eventually efforts led to the development of the NEPA, the National Environmental Policy, which called for a Council on Environmental Quality.

Recognizing the need to shift from end-of-pipeline control to pollution prevention, by the 1980s, the EPA established the Office of Pollution Prevention and Toxics. Two decades after the implementation of the EPA, The Pollution Prevention Act (1990), (http://www.epa.gov/p2/pubs/p2policy/act1990.htm), was created to enforce eco-friendly strategies, and provide grants to states in the effort to reduce source waste. President Bill Clinton devised the Presidential Green Chemical Challenge Awards during his presidency to reward those practicing sustainable chemistry. By the end of the 1990s, “Twelve Principles of Green Chemistry” was published. The guidelines serve as a reference for processes and practices to lessen negative environmental impact. These principles are Prevention i.e., It’s better to prevent waste than to treat or clean waste after it’s been created, Atom Economy, Less Hazardous Chemical Syntheses, Designing Safer Chemicals, Safer Solvents and Auxiliaries, Design for Energy Efficiency, Use of Renewable Feedstocks, Reduce Derivatives, Catalysis, Design for Degradation, Real-time analysis for Pollution Prevention and Inherently Safer Chemistry for Accident Prevention. For a description of these principles, click here: http://www.epa.gov/gcc/pubs/principles.html

As reflected in the previous decade spanning to today, there has been a shift in the emergence of green chemistry trends. As eco-awareness spreads to the consumer market and as the hazards of certain materials and chemicals become better known, companies and manufacturers are working to revamp the way they use chemicals in their products. These practices include:

Reducing formaldehyde (a gas linked to various health issues including cancer) use in the production of products.

Eliminating/reducing dyes in manufacture. Eliminating ozone-depleting CFC’s in widely used products. Development of technology through chemicals that lessens green impact (i.e.

converting sustainable plant-based materials to low-carbon chemicals). Creating a patented system to formalize and phase out raw materials for fabrication processes.

Developing sustainable technology used in agrichemical treatment for farming.

A Timeline of Green Chemistry Highlights

1962 - Rachel Carson, writer, biologist and environmental conservation icon, publishes the first of three installments of “Silent Spring,”—­literature that is historically tied to the launch of the environmental movement. The publication helped spread public awareness of the hazards of environmental pollution and pesticides to the environment.

1969 - President Richard Nixon establishes the Citizen’s Advisory Committee on Environmental Quality and a Cabinet-level Environmental Quality Council. (http://www.presidency.ucsb.edu/) Later that year, Nixon expanded his environmental efforts by appointing the White House Committee to determine whether an environmental agency should be developed.

1970 -The Environmental Protection Agency (EPA) is born.

1980s/1988 - Shift from end-of-pipeline control to pollution prevention is recognized, leading to the Office of Pollution Prevention and Toxics in 1988.

1990 - The Pollution Prevention Act under the George H.W. Bush Administration is passed.

1993 -The EPA implements the Green Chemistry Program, which serves as a precedent for the design and processing of chemicals that lessen the negative environmental impact.

1995 & 1996 - In 1995, President Bill Clinton established the Presidential Green Chemical Challenge Awards, which served to encourage those involved with the manufacture and processes of chemicals to incorporate environmentally sustainable design and processes in their practices. The following year, the first recipient receives the award, the only award issued by the president that honors work in chemistry. Source: http://portal.acs.org/

1997 - The Green Chemistry Institute is launched. Its vision is “…to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people.” Source: http://portal.acs.org/

1998 - “Twelve Principles of Green Chemistry” is published by Paul Anastas (of the EPA) and John Warner. 2000s-Present - In the past decade, some major green chemistry achievements include the California Green Chemistry Initiative.Governor Arnold Schwarzenegger signed the bills to in 2008, which serve to develop policy options for green chemistry. Source: http://www.dtsc.ca.gov One year later, President Obama nominated Paul Anastas (of Yale) as head of Research and Development at the EPA.

Additional Considerations: Chemical Risks

Experts claim that one of the first steps toward green chemistry practice is assessing materials that are unsustainable and working with manufacturers or developers to replace them with safer or more sustainable materials. Some major risks to evaluate include: pesticides released in farming, the release of harmful toxins during processes and in products, and indoor and outdoor emissions that pose a threat to health and air quality.

Additional Sources:

http://www.epa.gov/history/topics/epa/15c.htm

http://library.certh.gr/libfiles/PDF/GEN-PAPYR-4555-GREEN-CHEM-by-LINTHORST-in-FOUND-CHEM-V-12-SS--PP-55-68-Y-2010.pdf

http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_ARTICLEMAIN&node_id=830&content_id=CNBP_026133&use_sec=true&sec_url_var=region1&__uuid=08dc7152-55cc-45b2-a351-1ad7e966d610

http://engineering.dartmouth.edu/~cushman/courses/engs171/GreenChemistry.pdf

http://www.zerowaste.org/publications/gc_pres/index.html

Epoxy Essential

Epoxy, or polyepoxide, serves as a thermosetting polymer that initiates polymerization (also known as curing) when mixed with a hardener. The polymer itself is gleaned from a chemical reaction—usually between epichlorohydrin and bisphenol-A—which results in an epoxy resin. Epoxy can be modified to serve a multitude of purposes, but is most commonly found in paints, coatings, and adhesives.

Epoxy: Paint, Coatings, and Adhesives

One of the most standard epoxy coatings is a two-part waterborne coating—it is UV resistant, extremely hard, and resists abrasion. As a result of these properties and because of its excellent adhesion, it is commonly used to coat metal and other components that must withstand a fair amount of wear-and-tear. Additionally, waterborne epoxy coatings are less toxic than solvent-based epoxies, meaning they’re easier and safer to work with and dispose of. Industrial and automotive demands are high for waterborne epoxy because the coating is quite heat resistant, which reduces the chances of eventual peeling as a result of burning or heat intolerance. As with most epoxy, waterborne epoxy coatings harden and dry quickly once mixed with the appropriate hardener, so timely application is essential.

Polyester epoxy includes powder coatings, which are a common choice in coating white metal, such as refrigerators. Fusion bonded epoxy powder coatings can be used to line potable water pipelines, and are also used to reinforce concrete and prevent corrosion in standard steel pipes. Epoxy can also serve as a primer in applications that are prone to rust and corrosion, as it helps other coatings adhere.

As an adhesive, epoxy is widely used in the construction of automobiles, boats, bicycles, airplanes, and numerous other components that are routinely expected to maintain high levels of performance while exposed to the elements. Epoxy is often cured using heat—epoxies cured using heat tend to exhibit higher heat and corrosion resistance than those cured at room temperature—a cured epoxy demonstrates higher heat resistance, up to 350 degrees Fahrenheit, than most other common adhesives. They can be manipulated to be fast or slow setting, clear or opaque, malleable or rigid. They also work well as adhesives on solid wood furniture, stone, and glass, and can easily by altered to suit and array of applications.

Other Applications

Epoxy use isn’t limited to adhesive and coating applications, but serves a wider range of industries—epoxy can be found in industrial tooling, electrical systems, and in marine and aerospace fields.

In industrial tooling applications, epoxy is used to manufacture molds, models, castings, and fixtures to replace traditional metal and wood versions of the same. Epoxy can also be used to replace polyester resins and vinyl resins in fiber-reinforced parts and though they are somewhat more expensive the parts tend to be strong and temperature-resistant.

Because epoxy resins are good insulators, they are commonly used in integrated circuits, transistors, and hybrid circuits to protect the electrical components from external dirt, dust, and moisture. In large circuit board applications, epoxy is used to bind together various components and even comprise part of the soldering mask.

Epoxy can serve as a nice clear coating, but with additives can easily be transformed to resemble treated granite and a variety of other looks—this cuts down on the cost of materials like stone, while providing the treated surface with the benefits and strength of a traditional epoxy coating.

Industrial Products : Chemical Hazards Labels

Industrial Products: Chemical Hazard Labels

There are many different chemicals used for many different purposes. Chemicals can be very dangerous. In order to make consumers aware of the dangers of certain chemicals, the National Fire Protection Association (NFPA) has come up with a system to indicate the health, reactivity, and flammability of chemicals. This system includes the use of number and color codes in which red stands for flammability, yellow for reactivity, blue for health, and white for special precautions.

Hazard Ratings Summary:

Health – Blue

4 – Danger – Can be fatal even with shot exposure, protective equipment is required.

3 – Warning – Material is toxic or corrosive, skin contact and inhalation should be avoided.

2 – Warning – Can be harmful if absorbed or inhaled.

1 – Caution – Can cause minor irritation

0 – No known hazard.

Reactivity – Yellow

4 – Danger – At room temperature, the material is explosive.

3 – Danger – Can be explosive if mixed with water, heated under confinement, or shocked.

2 – Warning – Unstable and can react violently when mixed with water.

1 – Caution – Can react when mixed with water or heated but not violently.

0 – Stable – When mixed with water, material is not reactive.

Flammability – Red

4 – Danger – An extremely flammable gas or liquid.

3 – Warning – Flammable liquid with a flash point below 100 degrees Fahrenheit.

2 – Caution – A combustible liquid that has a flash point between 100 and 200 degrees Fahrenheit.

1 – Combustible when heated.

0 – Not combustible.

Special Precautions – White

Oxy – Oxidizing Agent

W – Water Reactive

Further Resources:

Chemical Hazards – A pocket guide to chemical hazards from the CDC with information on over 600 different chemicals.

About Chemical Hazards – An article explaining what a chemical hazard is, as well as information on what to do if exposed to hazardous chemicals.

Chemical Hazard Safety – In-depth safety data on chemicals including children's health, environmental safety, and other resources.

NFPA – The website of the National Fire Protection Association, the organization responsible for chemical hazard label safety.

Chemical Hazard Label – An article explaining chemical hazard labeling including charts explaining each label.

Chemical Reactivity – An in-depth article featuring a scientific explanation of chemical reactivity and how it works.

Chemical Safety – An overview of chemical safety featuring databases containing health and chemical information.

Chemical Hazards – Information on chemical hazards from the World Health Organization.

Hardwood Floors : Cleaning and Maintenance

Why Maintenance is Essential

To prevent hardwood floor damage, experts and manufacturers suggest numerous treatments. Yet even with regular maintenance, all hard wood floors will begin to deteriorate over time. Damage can range from fading, in high traffic areas, to extensive warping and cracking from moisture exposure. Treatment—whether by waxing or power sanding —ensures a good aesthetic, a sanitary floor and a safe, inhabitable space. Typically, maintenance depends on a few key factors: type of finish, wood grain and the extent of damage.

Damage Prevention & Simple Treatment

Following simple maintenance steps will help ensure that a hard wood floor looks its best. While regular sweeping is recommended on a daily (or at least weekly) basis to prevent soot from seeping into the wood, experts recommend utilizing a dry or damp mop instead of a saturated mop. Water tends to expand wood grain and may warp the floor, especially on unfinished surfaces. To avoid denting, consider using vacuums that feature brush attachments rather than machines with beater bars. Additionally, although covering floors will delay fading from use and sunlight, the World Floor Covering Association (www.wfca.org), suggests avoiding mats with rubber backing and those that are non-ventilated, as these textiles will tear at the surface of the wood.

Consulting a manufacturer or specialist about cleanser treatment is essential, as not all wood floors and finishes are compatible with the same treatment products. Therefore, it is essential to know the type of floor finish that is being processed. Most floors are coated with polyurethane, a durable plastic coating. Manufacturers supply pre-finished wood floors that have been UV dried and treated with polyurethane. Typically, these chemically treated floors are stain resistant, though the finish will eventually wear off. Hardwood floors that are treated with lacquer, varnish and shellac provide a shiny finish but do not resist stains and wear as well as polyurethane. Generally, denatured alcohol removes shellac and lacquer thinner, and acetone-based products are efficient for removing lacquer and varnish. Other wood floors are surface sealed with oil finishes, though these types of surfaces are typically coated with wax. Keep in mind that some paste waxes may require the use of a machine buffer.

As a general rule, experts recommend avoiding all oil-based soaps and waxes, specifically on polyurethane treated floors. Oil based wax sprays that accumulate create an unwanted film and a slippery floor, and may actually affect the re-coating process. Instead, a neutral pH cleaner is sufficient for most hardwood floors. For light treatment, a finish may be applied to fix fading. It is advised to apply coatings an hour apart. Additionally, finishing should be reserved for spot treatments for smaller areas of the wood surface.

Moderate to Heavy Damage

Screening is generally applicable to floors that have moderate damage. This process essentially involves utilizing a floor polisher to lift or abrade polyurethane finish off the wood without removing or cutting the floor. Experts advise that this process should be exclusive to floors with a polyurethane finish and floors that have not been treated with wax. Additionally, wood that is damaged beneath the finish is not compatible with this application, and should be sanded instead. Specialists note that it is essential to sweep the floor so that abrasives or dirt are not pushed into the surface during this process.

Power sanding may be essential to repair worn down areas of the finish and to treat heavy damage. Typically, a drum sander is employed, and it is advised to consult specialists for this procedure as the tool may gouge wood if it is not utilized properly. As a general guideline, a finish should be applied no more than 12 hours after a hard wood floor has been sanded. Typically, freshly sanded hard wood will absorb moisture and change color, which may adversely affect the finishing process.

Sometimes, corrosion will penetrate the finish of the wood, which will require extensive restoration. In the case of a flood, experts recommend the use of a mild alkali to scrub the contaminants from the wood surface. A trisodium phosphate is suitable for mildew scrubbing (and grease stains) and can be dried off with an absorbent cloth. For mildew build-up underneath the finish, it is essential to strip the coating. After sanding, experts may advise applying several applications of chlorine bleach to badly damaged parts of the wood. Afterwards, clean water may be used to rinse the wood, which should then be air dried. To prevent excessive warping and buckling, allow for sufficient drying time before the wood is refinished. For major damage where the wood is lifting, experts recommend nailing the wood to stop the damage from spreading.

Replacement of the wood may be necessary if the damage is too extensive. Some may opt to cover the wood with other materials like vinyl or carpeting or to replace the floor. Either way, consulting a contractor is recommended.

Antireflection Coating

Antireflection coatings are optical coatings that are typically used to decrease an object’s reflectivity. Depending on the exact composition of a given antireflection coating, the extent to which reflectivity can be reduced varies. No matter how antireflective a coating is each antireflective coating is made the same way: alternating layers of materials with opposing refractive index are layered to block certain wavelengths of light and transmit the desired spectrum. Antireflective coatings are typically designed to affect infrared, visible or ultraviolet light, depending on the application, with some coatings blocking a greater range of light than others.

Product Variants: Types of Antireflection Coatings

Typically, antireflection coatings are classified based on the number of layers: single- or multi-layer. A third kind of antireflection coating, called absorbing antireflection coating, is also available.

Key Terms

When considering types of antireflection coating and optical coatings in general, it’s helpful to understand a coating’s relationship to wavelengths of light, as well as various key terms.

Thick-film If a coating is referred to as thick-film, the film is thicker than the wavelength of light hitting the coating. Of course, the effect a coating has on reflectivity will depend not only on the light’s wavelength, but the angle at which light hits the coating’s surface. Typically, thick-film coatings increase reflectivity.

Thin-Film A thin-film antireflection coating is one that features a thickness that is a quarter of the thickness of the wavelength of light. As a result of this ratio, thin-film antireflection coatings reduce reflectivity.

Thin-Film Interference Thin-film interference can occur when the upper and lower layers of an antireflective coating reflect incident light waves. These light waves then interfere with each other and merge to form another light wave. Thin-film interference can sometimes indicate the coating’s thickness or refractive index.

Other Considerations

Other terms, such as broadband, narrowband and dual band, are often used to describe the kind of spectrum of light an antireflective coating is designed to block. For example, some high-efficiency coatings block infrared light. Broadband coatings, on the other hand, reduce reflectivity over a wide range of wavelengths, which enables more light to be transmitted and enhances contrast in some optical applications. Depending on the exact spectrum of light that one is trying to transmit or block, one of these coating options may be appropriate.

Optical Coating

Optical coatings are used primarily to coat optical devices, such as lenses and mirrors, to alter the way light interacts with the device. Because optical devices depend on either the proper transmission or reflection of light, the presence of an optical coating enables the device to function properly and achieve the level of transmission or reflection

needed. The process by which an optical device is made more reflective is called silvering—highly reflective metals, such as aluminum and silver, are often used in optical coatings to silver an optical device. Optical devices that require minimized reflectivity, on the other hand, tend to benefit more from antireflection coatings. Product Variants: Types of Optical Coatings

Depending on the desired result—either increased or decreased reflectivity—various optical coatings can be applied to create or enhance a device’s properties.

Key Terms

There are several key terms that may help during optical coating selection: dielectric, refractive index, reflective, antireflective broadband, wavelength and visible spectrum.

Dielectric

A dielectric material is an insulator, meaning it is not a good conductor of electric current. However, dielectric materials can support electrostatic fields, with makes them relatively versatile materials.

Refractive Index

A refractive index, also called an index of refraction, is a measure of a material’s ability to slow down light waves as they pass through. A material’s index of refraction is determined by the ratio of the speed of light in a vacuum to the speed of light in the material.

Reflective

A reflective material does not transmit light waves, but rather bounces light waves back. A mirror is an example of a highly reflective material.

Antireflective

An antireflective material is the opposite of a reflective material. Instead of reflecting light waves, an antireflective material reduces reflection, which can, in some cases, improve contrast.

Broadband

The term broadband refers to having a wide band (and a continuous spectrum) of electromagnetic frequencies. Sunlight is an example of a type of broadband light radiation.

Wavelength

A wavelength is the distance between one peak of a wave and the next; in this context, between one peak of a wave of light and the next.

Visible Spectrum

The visible spectrum refers to the range of wavelengths of visible light radiations, as can be seen in the distribution of colors created when light is dispersed by a prism.