JPH04107238A - Corrosion resistance and wear resistant cermet - Google Patents

Abstract

PURPOSE:To obtain cermet excellent in wear resistance and corrosion resistance, at the time of manufacturing a cermet by subjecting the powder of a hard material such as the carbides, nitrides and carbon nitrides of specified metals to compacting and sintering together with metallic powder for a bonding phase, by using an Ni allay having a specified compsn. as the metal for a bonding phase. CONSTITUTION:At the time of manufacturing cermet by mixing a mixture of the metallic compound powder and metallic powder having high hardness such as the carbides, nitrides and carbon nitrides of the group IVa, Va and VIa metals in a periodic table such as Ti, Zr, V, Cr, Mo and W with metallic powder as a binder at the time of sintering, compacting this mixed powder and thereafter executing sintering at a high temp., as the binder, mixed powder having a compsn. constituted of, by weight, 0.1 to 15% Mo, 1 to 15% Cr, 5 to 10% Cu and the balance Ni is used. The cermet excellent in corrosion resistance without damaging the high hardness and high strength of itself can be manufactured.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a cermet useful as a constituent material of various parts such as rings, bearings, sleeves, etc., which require both wear resistance and corrosion resistance. Conventional technology] TVa has traditionally been used as a cermet having the above characteristics.
In the combination of hard phases such as carbides, nitrides, carbonitrides, etc. of Group VIa metals with a binder phase, the above characteristics can be improved by blending various elements with Co, Ni, Mo, etc. that form the binder phase. We are trying to

For example, in JP-A-57-203745, N1 as the bonding phase contains W, V, Ti, Ta, Nb, and Zr.

Blending high melting point metals such as Hf to improve wear resistance,
Furthermore, it is disclosed that Zl:Cu is contained in an amount of 1 to 5% by weight to improve corrosion resistance and oxidation resistance.

[Problem to be solved by the invention]

The problem to be solved by the present invention is to further improve the corrosion resistance of the cermet without any deterioration of its properties such as wear resistance.

[Means to solve the problem]

The present invention provides a cermet consisting of a hard phase such as carbides, nitrides, carbonitrides, etc. of group metals a, Va, and Via, and a binder phase, in which the binder phase contains 0.1 to 15% by weight of Mo and 1% by weight of Cr.
The above-mentioned problem was solved by creating a composition containing 15% by weight of Cu and 5-10% by weight of Cu, with the balance being N1.

The above-mentioned Mo and Cr may be metal molybdenum and metal chromium, respectively, or M 02 C.

It may be in the form of a compound such as Cr5Cz.

[Effect]

The present invention shows that, contrary to the conventional general understanding, the effect of improving corrosion resistance by adding Cu in the binder phase is
This is based on the new knowledge that when the Ni content is 0% by weight, Cu becomes a solid solution in Ni and the passive region expands.

In the same composition, the significance of blending λ, -〇 and Or and the reason for limiting the blending amount are as follows.

Mo suppresses grain growth, improves the wettability between the hard phase and the binder phase, and improves sinterability. However, if the amount is too small, the desired effect cannot be obtained, and it is difficult to add a large amount. To reduce needle abrasion, the content should be reduced to 0.0% relative to the binder phase.
The content was determined to be 1 to 15% by weight.

Cr improves corrosion resistance, but if the amount is too small, the effect is weak, and as the content increases, the effect increases. However, if the content exceeds 15% by weight based on the binder phase, the effect is almost saturated, and the strength and hardness decrease. Preferably, 3 to 15% by weight of the binder phase provides the best corrosion resistance.

Furthermore, like Cr, Cu has the effect of increasing corrosion resistance, but this effect is obtained when the content is 5% by weight or more relative to the binder phase, and it is strengthened as the amount is increased; If it exceeds 5% by weight, grain growth occurs and the strength decreases, so the content was set at 5 to 10% by weight based on the binder phase.

〔Example〕

After blending an appropriate amount of powder with the composition shown in the table on the next page, and grinding and mixing this blended powder in a ball mill, 5×10×3Qm
Sample material A-
I created G.

The binder phase composition and properties of each sintered specimen are shown in the same table.

From this we can say the following.

Sample material B that does not contain Cu has hardness (H1^): 91.9,
The transverse rupture strength was +180 kg/mm', and the hardness (HR^) of test materials C to G containing Cu was in the range of 916 to 92.0, and the transverse rupture strength was in the range of 166 to 202. From this C
Even when u is contained, there is almost no decrease in hardness and there is almost no deterioration in wear resistance.

(Hereinafter, the margin of this page) Next, the corrosion resistance of the cermet of the present invention was tested using a potentiometer (constant electrolysis device), and the anodic polarization curve was measured by a constant potential method under the following conditions.

IN H2S01 solution (liquid temperature 35°C), lXl0-'V/ from the natural potential without gas blowing or stirring.
The electrode potential and current were measured by changing the potential at a rate of 1 sec.

The results are shown in FIG.

The following can be said from the figure.

(2) It can be seen that as the amount of Cu in the bonding phase increases, the anodic polarization curve shifts to the lower current density side as a whole, resulting in excellent corrosion resistance.

(2) It can be seen that as the amount of Cu in the binder phase increases, the passive region becomes wider, resulting in superior corrosion resistance.

These effects are obtained when the amount of Cu is 5 to 10% by weight.

(2) It can be seen that when Cr is added, the self-potential becomes high, the current density decreases overall, and the corrosion resistance increases.

These effects are due to the fact that Cu and Cr are dissolved in Nl.

[Effect of ribbing]

This development can bring about the following effects.

(1) It is a cermet with excellent wear resistance and corrosion resistance, with no changes to the conventional basic composition.

(2) Therefore, there is no need to fundamentally change the conventional manufacturing method.

(3) It has excellent corrosion resistance without reducing the hardness and strength of conventional cermets. Therefore, it is used as corrosion-resistant and wear-resistant parts such as mechanical rules that require these properties.

[Brief explanation of drawings]

The attached diagram shows TiC-14%M02c 18%W C6
%cr3cz-16%Nl is a diagram showing anodic polarization curves when the amount of Cu in the bonded phase is changed.

Claims (1)

[Claims] 1. In a cermet consisting of a hard phase such as carbides, nitrides, carbonitrides, etc. of group IVa, Va, and VIa metals and a binder phase,
A corrosion-resistant and wear-resistant cermet in which the binder phase contains 0.1 to 15% by weight of Mo, 1 to 15% by weight of Cr, and 5 to 10% by weight of Cu, with the balance being Ni.