Surface Heat Treatment

A proper surface treatment is essential to part performance. However, the technical details of many surface treatment processes are proprietary. Furthermore, the complexity and versatility of these processes make reverse engineering of surface treatment very challenging. The three most commonly used surface treatment techniques are surface heat treatment, protective coating, and shot peening. 

Electroplating is usually further specified by the plating alloy, such as nickel plating and silver plating. Nickel plating is applied to metal parts to 

Surface hardening and hardness measurement. (Reprinted from Rolinski, E. et al.. Heat Treating Progress, September/October, 6 19-23,2006. With permission.) 

The deposition processes also have three primary categories physical vapor deposition (PVD), chemical vapor deposition, and ion implantation. 

These depositions are often applied to the delicate instruments, such as medical and electronic devices. AMS 2403 and 2424 cover the materials, methods, applications, and processes for nickel electrodeposition and the properties thereof this deposition. They provide a wealth of information helping to decode this process in reverse engineering. 

---

Heat transfer between bed/surface Heat treatment of glasses, rubber, textile fibres... 

Surface heat treatment Resistance to abrasion, resistance to fatigue, sliding property... 

As a consequence of a decrease in the physical dimensions of the MgO particles, thermogravimetric profiles of PLLA/MgO composites can be shifted to lower temperatures due to an increase in the catalytic surface area [59]. However, decreasing the dimensions can cause other side reactions with unfavorable products (e.g., cyclic oligomers and m o-lactide) owing to the presence of different chemical structures/species on the MgO surface. Heat treatment of the MgO particles effectively suppressed oligomer production and enhanced the formation of L,L-lactide, indicating that the surface chemical properties of MgO also considerably influence the depolymerization of PLLA. 

Surface modification refers to the modification that occurs only on the surface of a polymer material without further internal modification. Surface modifications of polymeric materials include surface chemical oxidation, corona surface treatment, surface flame treatment, surface heat treatment, surface plasma treatment, surface metallization processing, ion implantation, and surface grafting polymerization. Because surface modification occurs only on the surface of materials, the performance does not change uniformly. 

More recently, surface heat treatments—using cooking, steam or hot water 26 -129a infra-red rays —have been developed for... 

Similarly, the technical requirements, quality assurance, applicable reference documents, and other notes related to the surface heat treatment procedure are also detailed in their respective material specifications. For example, AMS 2759/6 covers the surface heat treatment gas nitriding, while AMS 2759/8 covers ion nitriding. Reverse engineering of ion nitriding should refer fo AMS 2759/8 for guidance. Surface enhancement treatment, however, is beyond just surface heaf freafmenf, and this subject will be discussed in more detail in the next section. 

These effects can be illustrated more quantitatively. The drop in the magnitude of the potential of mica with increasing salt is illustrated in Fig. V-7 here yp is reduced in the immobile layer by ion adsorption and specific ion effects are evident. In Fig. V-8, the pH is potential determining and alters the electrophoretic mobility. Carbon blacks are industrially important materials having various acid-base surface impurities depending on their source and heat treatment. 

There are complexities. The wetting of carbon blacks is very dependent on the degree of surface oxidation Healey et al. [19] found that q mm in water varied with the fraction of hydrophilic sites as determined by water adsorption isotherms. In the case of oxides such as Ti02 and Si02, can vary considerably with pretreatment and with the specific surface area [17, 20, 21]. Morimoto and co-workers report a considerable variation in q mm of ZnO with the degree of heat treatment (see Ref. 22). 

Uses. Alkah metal and ammonium fluoroborates are used mainly for the high temperature fluxing action required by the metals processing industries (see Metal surface treatments Welding). The tendency toward BF dissociation at elevated temperatures inhibits oxidation in magnesium casting and aluminum alloy heat treatment. 

The stabihty of a particular treatment is also important. The enhancement should survive during normal wear or display conditions. Whereas all the enhancements from heat treatments are stable, some produced by irradiation are not. There are also surface coatings which wear off, oilings which dry out, etc. 

These processes may be followed by heat treatment and pressing with engraved roUs to produce the desired grain surface. 

Because the time at high temperature is much less, austenite is produced, which is chemically inhomogeneous especially with undissolved carbides, and has a fine grain crystal size. The formation of the hard martensite requites more rapid cooling than for conventional hardening. Thus case hardening by heat treatment intrinsically requites that the surface region to be hardened be relatively thin and cooled rapidly. 

Selective Carburi ng. In most components, it is desirable to carburize only parts of the surface. To prevent other regions from carburizing, they must be protected. For holes, simple plugs of copper may be used. In some cases, copper plating can be appHed, but diffusion into the steel must be considered, and the copper may have to be machined off later. Coatings (qv), which can be appHed as a paste and then removed after heat treatment, are also available and include copper plating, ceramic coatings, and copper and tin pastes. 

---