JPH032365A - Chemical resistant film - Google Patents

Abstract

PURPOSE:To provide the chemical resistant film which does not lose functions, such as wear resistance and chemical resistance, even in high-concn. chemicals, such as acids and alkalis, by forming the film as the nitride of Nb and/or Ta by an ion plating method. CONSTITUTION:Au NbN film and/or TaN film is formed on a base material consisting of metals, plastics, ceramics, etc., by using metal Nb and/or metal Ta as an evaporating source and by using a known ion plating method preferably consisting of a vacuum arc discharge type. The reactive gas to be used at the time of forming the above-mentioned nitride is exemplified by a gaseous mixture composed of N2, NH3 and water, etc. The above-mentioned film is formed simply by impressing a negative bias voltage on the above-mentioned base material while introducing the above-mentioned reactive gas into the ion plating device, then forming the formed nitride on the surface of the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a chemical-resistant coating that is resistant to chemicals such as acids and alkalis.

[Prior art] In order to improve wear resistance, titanium nitride (Ti
It is known to coat the surface of a material with a film such as N) or zirconium nitride (ZrN). However, it has been observed that these metal nitrides are eluted when exposed to highly concentrated chemicals such as acidic gases or solutions such as hydrochloric acid and sulfuric acid. In particular, nitride ceramics
It easily dissolves in nitric acid and loses its function as a protective film and wear-resistant film. Furthermore, although there are various corrosion-resistant coatings for wet plating, there is no such strong acid coating that functions as a protective coating other than gold plating. Furthermore, some organic paints are resistant to strong acids, but have the disadvantage of being weak to alkalis.

Therefore, no protective coating has been developed that is wear resistant and resistant to chemicals such as acids and alkalis.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a coating that does not lose its wear resistance and chemical resistance even in chemicals such as highly concentrated acids and alkalis in order to solve the above problems. It's about doing.

[Means for Solving the Problems] In order to achieve the above object, the present invention is characterized in that niobium (Nb) and/or tantalum (Ta) are formed as a nitride by an ion plating method.

[Function] When forming the film by ion plating, metal Nb and metal Ta may be used as evaporation sources.

The base material on which the film is formed is not particularly limited, and may include metals, alloys,
Examples include plastics, ceramics, and mixed materials thereof. Further, another coating, such as a metal nitride, oxide, or carbide, may be previously formed on the surface of these base materials. Nb and Ta
must be formed as a nitride film on the surface of the substrate, but niobium nitride (NbN) and tantalum nitride (TaN)
Either of these may serve as the lower layer, or the film may be formed in a state where NbN and TaN are mixed.

For the ion plating method used in the present invention, any known apparatus may be used, but a vacuum arc discharge type is preferably used. Reactive gases used when forming Nb and Ta nitrides by the ion plating method include nitrogen, ammonia, and mixed gases thereof, and the reactive gases are introduced into the ion plating apparatus. At the same time, a negative bias voltage may be applied to the base material, and the generated nitride may be formed on the surface of the base material. Examples of chemicals with which the film is durable include acid solutions such as hydrochloric acid, sulfuric acid, and nitric acid, alkaline solutions such as potassium hydroxide and sodium hydroxide, and gases thereof.

[Example] 601 mm x 301 mm, 3 mm thick stainless steel (SO
3304) The substrate was cleaned with an organic solvent and attached to a vacuum arc discharge type ion plating device. An Nb target with a purity of 99.9% was used as an evaporation source.

First, after reducing the degree of vacuum to I x 10-'Torr or less,
The base material was cleaned and heated by ion bombardment. Next, nitrogen gas was introduced as a reactive gas, and the pressure in the device was increased to 30
mTorr. In film formation, 100% was applied to the Nb target.
A current was applied, Nb ions were released by vacuum arc discharge, and NbN was formed into a film for 45 minutes on the base material to which a bias voltage of -300V was applied. Furthermore, in order to cover the part that was supporting the base material, the supporting location was changed and the film was formed for 45 minutes. Furthermore, a Ta target with a purity of 99.9% was used as an evaporation source, and the current value flowing through the target was 15%.
The same procedure as above was carried out except that the Ta was applied to the base material.
A film of N was formed.

[Comparative example] Ti and Zr with a purity of 99.9% were used as targets, respectively, and T was produced in the same manner as in the example except that the current value was set to 90A.
Films of iN and ZrN were formed.

In order to check the chemical resistance of this coating, each coating material was
0 sheets each, 100% concentration hydrochloric acid (Hcl), nitric acid (II
NO3), phosphoric acid (+1.PO2), acetic acid (C)13
COOH), ammonia (N11.0I+) and 50
% concentration of sulfuric acid (lItSO*) and ■θ% concentration of sodium hydroxide solution for one week at room temperature. It was quantified using an analyzer (ICP). As a result, the numerical values shown in Table 1 were obtained.

TiN and ZrN are eluted in large amounts by acids such as hydrochloric acid, nitric acid, and sulfuric acid, but the NbN of the present invention is
Although it is slightly eluted with nitric acid and phosphoric acid, the amount is smaller than that of TiN and ZrN.

Furthermore, TaN is hardly eluted.

Table 1 [Effects of the Invention] As is clear from the above, the present invention provides a coating with excellent chemical resistance, which requires wear resistance in corrosive environments such as chemical plants. Suitable for parts.

Claims (1)

[Claims] A chemical-resistant coating characterized in that niobium and/or tantalum is formed as a nitride by an ion plating method.