Thermal cycling tests

Under micro-discontinuous chromium coatings, copper undercoats improve corrosion resistance. On non-conductors, especially on plastic substrates, copper is often applied before nickel-chromium plating over the initial electroless copper or nickel deposit in order to improve ductility and adhesion, e.g. as tested by the standard thermal-cycling test methods ... 

The arrangement is then placed in a furnace, heated to 800°C, and the pressure decay test is repeated. The setup can be subjected to thermal cycles with pressure decay tests at room temperature and at 800°C. A good hermetic seal, however, will not show any pressure decay at a low pressure differential. The results of one series of tests using a glass composite material that has a glass transition temperature (Tg) of about 700°C, at 5 psi are shown in Figure 5.10. The combination of pressure and thermal cycle tests showed that the seal is capable of withstanding the pressure... 

Tie and Mo powders were sprayed by the plasma twin-torch process to form an FGM layer over a substrate to be used as an emitter in a thermoionic energy converter. The sprayed TiC coatings showed high absorptance for solar radiation. As compared to Tie monolayer coating and Tie/Mo two-layer coating formed on Mo substrate, FGM coatings performed better in a thermal cycling test. 

Thermal cycle resistance of Tic, TiC-Mo andTiC/Mo FGM coatings were investigated by the thermal cycling test of temperature range between room temperature and 1223K in 5 times ( heating, cooling speeds were 100 K/s ) in air. ... 

Table 2 Results of thermal cycle test of coatings...

There are no recognizable defects in the FGM coatings after the thermal cycle test (from R.T. to 1223K, 5 cycles) while there are defects in the TiC single coating onto the Mo substrate. 

Finite element model analysis simulating the thermal cycle tests demonstrated that the top coat spallation of both types of coating is caused by the buckling driven by delamination due to the transient large in-plane compressive stress development immediately after initiate heating. 

The thermal resistance between substrate and coating is probably negligibly small since the coating adheres well to the substrate, particularly for the few thermal cycles tested over here. For the thermal conductivity contribution of the 403 stainless steel substrate, we use data obtained previously on 410 stainless steel [8], Figure 5 shows thermal conductivity as a function of temperature for 410 stainless steel as measured in the guarded hot plate. 

G.P. Bierwagen, J. Li, L. EUingson, D.E. TaUman, Studies of anew accelerated evaluation method for coating corrosion resistance-thermal cycling testing. Prog. Org. Coat. 39 (2000) 67—78. 

Sharma, S.D. Buddhi, D. Sawhney, R.L. Accelerated thermal cycle test of latent heat-storage materials. Sol Energ 66 (1999) 483-490. 

Silakhori, M. Naghavi, M.S. Metselaar, H.S.C. Mahlia, T.M.I. Mehrali, H. Fauzi, M. Accelerated thermal cycling test of microencapsulated paraffin wax/polyaniline made by simple preparation method for solar thermal energy storage. Materials 6 (2013) 1608-1620. 

Considering above mentioned facts, we have prepared test samples as shown in Table I. The combination of bisphenol-A and chainaliphatic amine, used in samples K-1 to K-5, is popular for use at low temperatures, and its strength has been confirmed by thermal cycle tests, where iron bolts have been imbedded in these... 

The objective of this research Is the examination of the effects of ion bombardment on the structure of thin ceramic films on ceramic substrates. The material combinations will Include oxide films that have (a) no solid solubility, (b) limited solid solubility, and (c) complete solid solubility with the substrate material (also an oxide). Techniques for determination of elastic and plastic properties of thin films or coatings on ceramic substrates and for the determination of the strength of the bond between the film and substrate, which are currently being developed, will be used to determine the hardness, elastic modulus, and adherence of each material combint tion. The main testing techniques will be the ultra-low load micro-indentation tester (Nanaindenter) and thermal cycling tests. 

Figure 21 Thermal cycling test of vibro-cast alumina and fused-cast alpha-beta alumina crucibles...

---