Quench hardening

PVD (physical vapor deposition) methods can be applied whenever the substrate temperature has to be kept lower than 600 °C (e.g. for quenched-hardened steel items) they make use of a variety of techniques ranging from sputtering to ion beam deposition. 

An industrial application described by Bessi6re and Martre was the use of sintered bronze/molybdenum disulphide bushes in a roller table of a system for quench-hardening heavy steel plates. The bearing experienced severe thermal cycles, and this seems the type of application for which metal composites are very appropriate. 

Fig. 12 (a) Chemical composition of D2/CVD TiN, measured by GDOS and (b) Chemical composition of D2/CVD TiN/quench hardened + tempered, measured by GDOS. 

Post quench hardening and tempering of D2/TiN does not influence the coating residual stresses significantly (Figure 16a). This is due to the almost equal specific substrate volumes... 

Fig. 16 (a) Residual stresses of D2/CVD TiN and D2/CVD TiN/quench hardened -i- tempered and (b) Residual stresses of L3/CVDTiN and L3/CVD TiN/quench hardened -i-tempered, measured by x-ray diffraction (sin xiz-method). 

Table 5. Residual Stresses in CVDTiN Coatings After Quench Hardening ...

Hardening Quench Hardening Quench Hardening + Tempering 500°C... 

In Table 5 the calculated changes in coating residual stresses after quench hardening are compared with values measured by x-ray diffraction. The agreement is quite good, so the described model can be used to predict residual stresses in CVD coatings after quench hardening. 

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