JPS62109962A - Alumina powder for thermal spraying - Google Patents

Abstract

PURPOSE:To obtain an alumina powder for thermal spraying forming a film improved in wear resistance and strength by plating the surface of alumina powder with specific proportion of nickel by use of an electroless plating method. CONSTITUTION:The surface of the alumina powder is plated with nickel in the ratio of nickel to alumina of 10-100pts.wt. to 100pts.wt. by the electroless plating method. On thermal spraying above-mentioned alumina powder on a material, the powder is uniformly dispersed in a state where nickel is allowed to adhere closely to alumina grains, so that porosity in the thermally sprayed film is reduced and further the bond between alumina and nickel grains as well as the one among alumina grains can be improved. In this way, a film improved in wear resistance and strength can be formed.

Description

【発明の詳細な説明】 産業上の利用分野 この発明は、溶射に用いられるアルミナ粉末に関する。[Detailed description of the invention] Industrial applications The present invention relates to alumina powder used for thermal spraying.

従来の技術 アルミナは、金属やプラスチックに比べ、耐摩耗性、耐
熱性、耐断熱性、耐食性などにすぐれている。このよう
なアルミナの性質を応用する技術として、アルミナ粉末
をプラズマなどの熱源によって溶融し、鋼板などに吹き
付け、皮膜を形成させる溶射技術があり、例えば製紙ロ
ーラやポンプに応用されている。ところで、溶射によっ
て得られるアルミナ皮膜と鋼板など素材とは、■熱膨張
率に大きな差がある、■素材に対する濡れ性が悪い、■
素材との間に化合物を作らない、等の理由から１、直接
素材に溶射する手段は採られていない。Conventional technology Alumina has superior wear resistance, heat resistance, heat insulation resistance, and corrosion resistance compared to metals and plastics. As a technology that applies these properties of alumina, there is a thermal spraying technology that melts alumina powder using a heat source such as plasma and sprays it onto a steel plate or the like to form a film, and is applied to papermaking rollers and pumps, for example. By the way, the alumina coating obtained by thermal spraying and materials such as steel plates: ■ There is a large difference in coefficient of thermal expansion, ■ Poor wettability to the material, ■
For reasons such as not creating a compound between the material and the material, 1. Direct thermal spraying onto the material is not used.

すなわち、従来は、 ■ニッケル・クロム合金などを下地として溶射した後、
アルミナ粉末を溶射する方法、＠金属粉末とアルミナ粉
末とを混合（サーメット）シて溶射する方法、 が採られていた。In other words, in the past, after spraying a nickel-chromium alloy as a base,
The following methods were used: thermal spraying alumina powder, and mixing metal powder and alumina powder (cermet) and thermal spraying.

発明が解決しようとする問題点 しかし、下地溶射を用いる前者（イ）の方法では、下地
溶射皮膜とアルミナ溶射皮膜の境界及びアルミナ溶射皮
膜内部において、粒子間結合力が小さく、十分な皮膜性
能が得られていない。一方、後者（嗜の方法では、かな
り多量の金属粉末が混合されるので、この方法で得られ
た皮膜はアルミナ本来の性質が十分に発揮されていない
。また、金属分散状態もあまり均一でないため、皮膜性
能が不均一となる。Problems to be Solved by the Invention However, in the former method (a) using base spraying, the interparticle bonding force is small at the boundary between the base sprayed coating and the alumina sprayed coating and inside the alumina sprayed coating, resulting in insufficient coating performance. Not obtained. On the other hand, in the latter method, a fairly large amount of metal powder is mixed, so the film obtained by this method does not fully exhibit the original properties of alumina.Also, the state of metal dispersion is not very uniform. , the film performance becomes uneven.

この発明は、アルミナ溶射皮膜内の粒子間結合力を向上
させ、かつ皮膜内気孔を減少させることにより、耐摩耗
性または皮膜強度を向上させるとともに、ニッケル・ク
ロム合金などの下地溶射を必要としないアルミナ溶射皮
膜をうげることのできる溶射用アルミナ粉末を提供する
ことを目的としている。This invention improves the bonding strength between particles within the alumina thermal spray coating and reduces the pores within the coating, thereby improving wear resistance and coating strength, and does not require base thermal spraying such as a nickel-chromium alloy. The object of the present invention is to provide an alumina powder for thermal spraying that can form an alumina thermal spray coating.

問題を解決するための手段 本発明の溶射用アルミナ粉末は上記問題点を解決するた
めに、無電解めっき法により、アルミナ粉末の表面に、
アルミナ１００重量部に対しニッケルを１０重量部から
１００重量部の割合でめっきしたもので５ンる。Means for Solving the Problem In order to solve the above problems, the alumina powder for thermal spraying of the present invention is coated on the surface of the alumina powder by an electroless plating method.
It is made by plating 100 parts by weight of nickel with 10 to 100 parts by weight of alumina.

なお、粒子の形状は球形に限らず、種々形状の粒子に本
発明は適用できる。Note that the shape of the particles is not limited to spherical, but the present invention can be applied to particles of various shapes.

作用 上記構成によれば、アルミナ粉末の表面に予めニッケル
が皮膜を形成しており、本発明アルミナ粉末を更に素材
に溶射した場合、ニッケルがアルミナ粒子に密接した状
態で均一分散化され、この結果、溶射皮膜中の気孔率が
減少し、まｔコ、密接した状態でアルミナとニッケルが
存在するため、アルミナ−アルミナ粒子間結合及びアル
ミナ−ニッケル粒子間結合が向上する。Effect According to the above configuration, a nickel film is formed on the surface of the alumina powder in advance, and when the alumina powder of the present invention is further thermally sprayed onto a material, the nickel is uniformly dispersed in close contact with the alumina particles, and as a result, The porosity in the sprayed coating is reduced, and since alumina and nickel are present in close contact with each other, the bonding between alumina and alumina particles and the bonding between alumina and nickel particles are improved.

こ−で、ニッケルの割合をアルミナ１００重量部に対し
１０重量部以下とした場合は、溶射皮膜中のアルミナ粒
子間結合が不充分であり、１００重量部以上とした場合
は、溶射皮膜中のアルミナ粒子間結合が向上する反面、
耐熱性や耐摩耗性が低下し１アルミナを溶射の本来の目
的が損われることになる。Therefore, if the proportion of nickel is less than 10 parts by weight per 100 parts by weight of alumina, the bond between the alumina particles in the sprayed coating is insufficient, and if it is more than 100 parts by weight, the bonding between the alumina particles in the sprayed coating is insufficient. Although the bond between alumina particles is improved,
The heat resistance and abrasion resistance will decrease, and the original purpose of thermal spraying 1-alumina will be lost.

実施例 以下本発明の一実施例を図百に基づいて説明する。第１
図は本発明の粉末の断面の一例である。EXAMPLE An example of the present invention will be described below with reference to FIG. 1st
The figure is an example of a cross section of the powder of the present invention.

アルミナ粉末（１）の表面にはニッケル（２）が１０重
量部から１００重量部の割合で無電解めっきされている
。The surface of the alumina powder (1) is electrolessly plated with nickel (2) in an amount of 10 to 100 parts by weight.

上記のように構成された溶射粉末を鋼板に溶射した場合
、溶射皮膜の断面は第２図のようになる鋼板（３）の表
面にはニッケル（２）がアルミナ（１）の皮膜中に分散
して存在する。気孔（４）も観察されるが、その量はか
なり少ない。When the spray powder configured as above is sprayed onto a steel plate, the cross section of the sprayed coating will look like that shown in Figure 2. On the surface of the steel plate (3), nickel (2) is dispersed in the alumina (1) coating. It exists as such. Pores (4) are also observed, but their amount is quite small.

上記のように構成された皮膜の性能の調査結果を以下に
述べる。下記の表は実験に供した溶射用アルミナ粉末で
、Ｎ１−２が本発明の溶射用アルミナ粉末である。The results of an investigation into the performance of the film constructed as described above will be described below. The table below shows the alumina powder for thermal spraying used in the experiment, and N1-2 is the alumina powder for thermal spraying of the present invention.

表 第３図は、上記表の各溶射粉末を鋼板に対しプラズマ溶
射法によって溶射し、得られた皮膜の断面を画像処理に
よって評価した結果を示しており、縦軸に面積率（９６
）を採っている。このｍ３図で明かなように、ニッケル
をアルミナ粉末を予め溶射した咎嚇歩命溶射粉末は、気
孔率を減じさせており（ＡＬとＮ１−１とＮ１−２の対
比）、ニッケルの量（重量％）をアルミナの】（重量％
）以上としても気孔率はそれほど大幅に変化しない（Ｎ
１−２とＮ１−８の対比）。Table 3 shows the results of spraying each thermal spray powder in the above table onto a steel plate using the plasma spraying method, and evaluating the cross section of the resulting coating through image processing. The vertical axis shows the area ratio (96
) is adopted. As is clear from this m3 diagram, the porosity of the thermally sprayed powder, in which nickel is pre-sprayed with alumina powder, is reduced (comparison between AL, N1-1 and N1-2), and the amount of nickel ( ](wt%) of alumina
) or more, the porosity does not change significantly (N
1-2 and N1-8).

なお、アルミナ・銅合金に銅めっきを施した溶射粉末（
ｃＵ）も、確かに気孔率が小さいが、後述するように付
着性に問題がある。In addition, thermal spray powder (copper plating applied to alumina/copper alloy)
cU) also has a low porosity, but has a problem with adhesion as described below.

第４図は、鋼板との付着性を評価した結果で、＃１４Ｉ
ｔｌ＋に破断応力（ＭＰａ）を採っている。なお（ＡＬ
−Ｍ）は、アンダーコートとしてＭＣｒＡＥＹ　　を施
行した後ＡＬ　（アルミナ粉末）をトップコートした試
料である。第４図で明らかなように、本発明のＮ１−２
ｆＪ高い付着性を有している。そして、より以上にニッ
ケルを増量したＮ１−８は、本発明のＮ１−２に比して
差がない。このことは、本発明以上にニッケルを加えて
も意味がないことを示す。また、ＣＵはは発明のＮｌ−
２に比べて破断応力が低い（付着性が低い）ことを示し
ている。Figure 4 shows the results of evaluating the adhesion to the steel plate, #14I
The breaking stress (MPa) is taken as tl+. In addition, (AL
-M) is a sample in which MCrAEY was applied as an undercoat and then topcoated with AL (alumina powder). As is clear from FIG. 4, N1-2 of the present invention
fJ has high adhesion. There is no difference in N1-8, in which the amount of nickel is increased, compared to N1-2 of the present invention. This shows that there is no point in adding more nickel than in the present invention. Also, CU is the invention's Nl-
This shows that the breaking stress is lower (lower adhesion) than in Sample No. 2.

第５図は、皮膜の耐摩耗性及び皮膜中の粒子間結合力を
評価するために行ったプラストエロージョン試験結果を
示したものである。本発明の溶射粉末であるＮ１−２で
は最も減少重量が少ない。FIG. 5 shows the results of a plasto-erosion test conducted to evaluate the abrasion resistance of the film and the bonding strength between particles in the film. N1-2, which is the thermal spray powder of the present invention, has the smallest weight loss.

硝明の＠果 以上説明したように本発明に依れば、強力な粒子間結合
が得られ、空気率が減少し、皮膜性状が均一化されて付
着力が向上し、また耐摩耗性が向上するという顕著な動
盤を奏する。As explained above, according to the present invention, strong interparticle bonding is obtained, air content is reduced, film properties are made uniform, adhesion is improved, and wear resistance is improved. It plays a remarkable movement board that improves.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明のアルミナ粉末の一例を示す断面図、第
２図は、本発明アルミナ粉末を用いた溶射皮膜の断面図
、第８図は皮膜断面のアルミナ。 ニッケル、気孔等の面積率を示すグラフ、第４図は鋼板
への皮膜の付着性を評価するグラフ、第５図は皮膜の耐
摩耗性及び皮膜中の粒子間結合力を評価するグラフであ
る。 （１）・・・アルミナ、（２）・・・ニッケル、（３）
・・・鋼板、（４）・・・気孔FIG. 1 is a cross-sectional view showing an example of the alumina powder of the present invention, FIG. 2 is a cross-sectional view of a thermal spray coating using the alumina powder of the present invention, and FIG. 8 is a cross-sectional view of the alumina coating. A graph showing the area ratio of nickel, pores, etc., Figure 4 is a graph to evaluate the adhesion of the film to the steel plate, and Figure 5 is a graph to evaluate the abrasion resistance of the film and the bonding force between particles in the film. . (1)...Alumina, (2)...Nickel, (3)
... Steel plate, (4) ... Pores

Claims (1)

【特許請求の範囲】[Claims] １、無電解めつき法により、アルミナ粉末の表面に、ア
ルミナ１００重量部に対しニッケルを１０重量部から１
００重量部の割合でめつきしたことを特徴とする溶射用
アルミナ粉末。1. Using an electroless plating method, nickel is added from 10 parts by weight to 1 part by weight to 100 parts by weight of alumina on the surface of alumina powder.
An alumina powder for thermal spraying, characterized in that it is plated at a ratio of 0.00 parts by weight.