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In order to make the mold endure much more high
temperature oxidation, resist corrosion in the process of make,
and enhance the ability to resist tribology, we usually coat a
protecting layer on the surface of the mold so as to extend
mold''s lifetime and to improve the precision of the worked. Hard
chromium, CrN, and TiN are hard coating layer which are used
much more frequently on the surface of the mold. First electric
coating hard chromium is provided with the advantage of its
simple process, and certain degree of protection for the mold.
Therefore it is always the main stream material of hard coating
layer used on the mold. Secondary TiN is provided with high
hardness, and substrate adhesion. Therefore, it can be used
largely on application of the mold. But the anti-oxidation and
the mold release ability are less idea than CrN coating layer.
In most of coating layers, people believe that CrN owing the
dense Cr2O3 oxidation layer on the surface is provided with this
kind of advantage. The coating layer deposited by UBM system
is usually noted for its smoothness and density. In the past few
years, the development of UBM system improve the evenness of the
coating layer''s large measure of area, and enhance the
efficiency of the deposition. This research here engages in
trying to deposit CrN, Cr2O3, and CrC layers by UBM system and
to study it''s high temperature oxidation and mechanical
property. We found out in the result of the research that CrN
produce a great quantity of oxidation in 700℃, Cr2N in 660℃,
CrC in 630℃. Through the oxidation test of one hour at 800℃ in
the constant temperature. We know that the depth of oxidation
lay lower than Cr2N and hard chromium. Thermogravimetric
analysis also testify that Cr2O3, formed by CrN, is provided
with the best protective for stainless steel substrate, and is
with the shape of crease structure. Moreover, property of anti-
oxidation of the Cr2O3 coating layer is not as expected, owing
largely to rupture caused by coating layer. But its surface is
pretty smooth after the process of thermal treatment. Cr2N''s
property of anti-oxidation is apparently less than CrN, but
better than TiN, and shape of its oxidation layer is presented
granular construction. The CrN, deposited in this research,
is found out that it''s CrN 2p3/2 binding energy is situated in
576.5 eV, Cr2N in 575.9 eV, and and Cr2O3 in 576.5 eV.
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