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Vitreous Coatings (new&better) [Coating Type]:

Vitreous coatings are thin layers of glass fused onto the surface of the substrate. When the substrate is a ceramic, the coating called a glaze. When the substrate is a metal, the coating is called porcelain enamel. When the substrate is a glass, the coating is called a glass enamel. A major reason for using vitreous materials for coating is their potential for chemical resistence in service . Among the many products which have vitreous coating for reasons of chemical resistance in service are chamical reactors, dental crowns, dinnerware, washing machine baskets etc.

(David E.Clark, Bruce K. Zoitos,Corrosion of Glass, Ceramics and Super Conductors, pg 372;  J.V. Koleske, Paint and Coating testing manual, pg 65)

Vitreous Coatings (Previous)

Vitreous coatings are smooth,nonpourus, bonded coatings that are resistant to temperatures up to 1800F for long periods. High temperature vitreous or glass refractory coatings are applied superalloy substrates by using modifications of existing enameleing materials. Improvements in vitreous coatings are made by adding refractory oxides to the basic formulation. This results in "matte" finish coatings that can protect from temperatures reaching 2200F. Ussually several layers of coating are built up on the substrate surface by additional coating-firing operations.

(National Research Council (US) Comitee on Coatings, High-temperature oxidation-resistant coatings, p 64-65)

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Powder Coating (new&better) [Coating Method]

Powder coating is a way of applying a dry paint to a surface. Most people have used liquid paints. They may have applied them with a brash, a spray can, or even with their fingers. Powder coatings are dry because there are no liquid solvents. The dry powder is applied to the item to be painted. Then the powder is turned to liquid by melting. That powder in its molten state subsequently flows out to cover the substrate; it coalesces and sometimes it crosslinks. The end result is a painted object.

(Laurence W. McKeen, Fluorinated coatings and finishes handbook, pg 147 )

 Powder Coating (previous)

Powder coating is a method for applying finely divided, dry solid resinous coatings by dipping products in a fluidized bed or by spraying them electrostatically on the part. The fluidized bed is essentially a modified dip tank. When charged powder particles are applied during the electrostatic spraying method, they adhere to grounded parts until fused and cured. In all case the powder coating must be heated to its melt temperature where a phase change occurs, causing it to adhere to the product and fuse to form a continuous coating.

Both thermosetting and thermoplastic powder can be applied by powder coating processes. Elaborate reclaiming systems to collect and reuse over-sprayed material in electrostatic spray powder systems boost transfer efficiency. Since the enhancement of the air quality standards this method has grown markedly. (Charles A. Harper, Edward M. Petrie, Plastic Materials and Processes- A Concise Encyclopedia, A John Wiley & Sons,Inc.Pub., 2003. p.457)

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Photopolymerization(new&better)  [Polymerization Process]

Photopolymerization is the process in which low molacular weight species (monomers, oligomers and prepolymers)are transformed into high molacular weight molacules to yield solid materials upon exposure to either visible or ultraviolet (UV)light. The light source can be either a laser or a polychromatic lamp. The advantages and benefits of UV photopolymerization are well known since their early industrial applications in mid-late 1970s:

1.       Rapid cure rate

2.       Energy and space saving

3.       Zero Volatile Organic Compounds

4.       Low-temperature operation

5.       Application versatility  can be counted as the most known advantages of the photopolymerization.

(Qin Li, Photopolymerization and characterization of thiol-enes and thiourethanes, pg. 1)

Photopolymerization (previous):

Polymerization is the process of linking small molecules (known as monomers) into chain-like larger molecules (known as polymers). When the chain-like polymers are linked further to one another, a cross-linked polymer is said to be formed. Photopolymerization is polymerization initiated by a photochemical process whereby the starting point is usually the induction of energy from the radiation source.

(Rapid Prototyping, Chua C. K., Leong K. F. and LIM C. S., Page 45)


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Tribocorrosion (new&better) [Material deterioration Process]

Tribocorrosion is a material deterioration process which results from the interaction of wear and corrosion that takes place in tribological contact exposed to aggressive environment. The lifetime and permormance of many mechanical devices, such as orthopaedic implants, food processing equipment and pumps for chemicals, is limited by tribocorrosion. However, in some applications tribocorrosion can be conveniently used for manufacturing and finishing purposes. For example, chemical-mechanical plishing (CHP) process is widely used in production of integrated circuits.

(Alfons Fischer,Kirsten BobzinFriction, Wear and Wear Protection, pg. 185)

Tribocorrosion (previous)

Tribocorrosion is an irreversible transformation of a material resulting from simultaneous physicochemical and mechanical surface interactions taking place in a tribological contact. Tribocorrosion involves numerous synergy effects between mechanical and chemical or electrochemical phenomena including corrosion accelerated occurs in many types of contacts such as sliding contacts, rolling contacts, fluid or particle impingement, as well as erosion and abrasion phenomena in fluids due to suspended particles. Technical systems of sliding contact in aqueous media are found for example in pumps, mining equipment, medical implants, metal grinding. Fretting corrosion is a particular case of tribocorrosion of solid-solid contacts resulting from low amplitude oscillations in a corrosive environment.

(Edited By: S. Virtanen, P. Schmuki, G.S. Frankel, Critical Factors in Localized Corrosion IV, p. 618)

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Control Charts (new&better)

As the world continues to strive for a global econemy, yhe marketplace is becoming fiercely competitive. With this competition comes the requirement to deliver products and services to existing customers as well as imroving products and services that appeal not only to current customers but to new and potential customers as well. With the production of quality products and services comes requiremenr of monitoring processes to ensure taht they are indeed producing a quality output. Control charts, or statisitical process control (SPC) charts are an excellent technique for accomplishing this requirement.

In the purest sense, a control chart is a line graph that displays an ongoing Picture of what is happening in a process. It is a graphical representation of the variation of a process with respect to time. Using control charts provides many benefits, some of which include:

1.      Gaining insight about the process

2.      Monitoring the process to observe its performance

3.      Identifying variation and the particular types of variations

4.      Monitoring and reducing the variation

5.      Determining the process capability

6.      Controlling the process

7.      Identifiying the presence of trends, shift, and other patterns in the process

(Mark A. Fryman, Quality and process improvement, Pg. 212)

Control Charts:
A control chart provides a basis for deciding whether the variation in the output is due to common causes (in control) or assignable causes (out of control). Whenever an out-of control situation is detected, adjustments or other corrective action will be taken to bring the process back into control.Control charts can be classified by the type of data they contain.

(D.R.Anderson, D.J.Sweeney,T.A.Williams, Statistics for Business and Economics, pg.852)