JP2719942B2 - Silicon nitride sintered body and method for producing the same - Google Patents

Silicon nitride sintered body and method for producing the same

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Publication number
JP2719942B2
JP2719942B2 JP63306320A JP30632088A JP2719942B2 JP 2719942 B2 JP2719942 B2 JP 2719942B2 JP 63306320 A JP63306320 A JP 63306320A JP 30632088 A JP30632088 A JP 30632088A JP 2719942 B2 JP2719942 B2 JP 2719942B2
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JP
Japan
Prior art keywords
sintered body
silicon nitride
content
weight
internal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP63306320A
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Japanese (ja)
Other versions
JPH02153865A (en
Inventor
淳一郎 鈴木
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NGK Spark Plug Co Ltd
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NGK Spark Plug Co Ltd
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Filing date
Publication date
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Priority to JP63306320A priority Critical patent/JP2719942B2/en
Priority to DE3939989A priority patent/DE3939989C2/en
Priority to KR1019890017810A priority patent/KR960016069B1/en
Publication of JPH02153865A publication Critical patent/JPH02153865A/en
Priority to US08/075,917 priority patent/US5316856A/en
Application granted granted Critical
Publication of JP2719942B2 publication Critical patent/JP2719942B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/597—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon oxynitride, e.g. SIALONS

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、窒化珪素基焼結体及びその製造方法に関
し、更に詳しくいえば靱性等の本質的特性を低下させる
ことなく耐摩耗性を向上させた窒化珪素基焼結体及びそ
の製造方法に関する。本発明の窒化珪素基焼結体又は本
発明の方法により製造された窒化珪素基焼結体は、切削
工具、耐摩耗部品及び摺動部品等に利用される。Description: TECHNICAL FIELD The present invention relates to a silicon nitride-based sintered body and a method for producing the same, and more specifically, to improve abrasion resistance without reducing essential properties such as toughness. The present invention relates to a silicon nitride-based sintered body and a method for manufacturing the same. The silicon nitride-based sintered body of the present invention or the silicon nitride-based sintered body manufactured by the method of the present invention is used for cutting tools, wear-resistant parts, sliding parts, and the like.

〔従来の技術〕[Conventional technology]

従来の窒化珪素基焼結体としては、耐摩耗性を向上さ
せるために、表面に高硬度又は耐摩耗性に優れるセラミ
ック材料を被覆したものが知られている（特公昭63−12
78号公報）。As a conventional silicon nitride-based sintered body, a sintered body having a surface coated with a ceramic material having high hardness or excellent wear resistance in order to improve wear resistance is known (Japanese Patent Publication No. 63-12 / 1988).
No. 78).

また、他の窒化珪素焼結体において、母材の改良とし
て高硬度のα−窒化珪素粒を強靱性のβ−窒化珪素粒中
に分散させたものも知られている（特開昭58−185484号
公報）。As another silicon nitride sintered body, there is also known a sintered body in which α-silicon nitride grains having high hardness are dispersed in tough β-silicon nitride grains as an improvement of a base material (Japanese Patent Application Laid-Open No. 58-1983). No. 185484).

〔発明が解決しようとする課題〕[Problems to be solved by the invention]

上記前者の焼結体においては、被覆セラミック材と窒
化珪素母材との熱膨張又は化学的親和性の相違という問
題により、十分な接着強度が得られにくく、更に費用も
かかり経済性にも問題があり、ほとんど実用化されてい
ない。In the former sintered body, it is difficult to obtain a sufficient adhesive strength due to a problem of thermal expansion or a difference in chemical affinity between the coated ceramic material and the silicon nitride base material, and furthermore, it is costly and economically problematic. There is almost no practical use.

上記後者の焼結体は、両相を全体に均一に含むので、
その割合により性能が変化するものであり、その各性能
を十分に発揮できない。即ち一方の性能を十分に高めよ
うとすると、他方の性能を犠牲にせざるをえず、バラン
スを保ってその中間性能を示すに過ぎない。Since the latter sintered body contains both phases uniformly throughout,
The performance varies depending on the ratio, and each performance cannot be sufficiently exhibited. That is, in order to sufficiently enhance one of the performances, the other performance must be sacrificed, and only the intermediate performance is maintained while maintaining the balance.

本発明は、上記観点に鑑みてなされたものであり、表
面を改良して耐摩耗性に優れた表面部を形成させて表面
部及び内部の材質特性を十分に発揮させた従来になく優
れた窒化珪素基焼結体及びその製造方法を提供すること
を目的とする。The present invention has been made in view of the above-mentioned viewpoints, and is an unprecedentedly superior surface-forming and surface-internal material property by forming a surface having excellent wear resistance by improving the surface. An object of the present invention is to provide a silicon nitride-based sintered body and a method for manufacturing the same.

〔課題を解決するための手段〕[Means for solving the problem]

本発明者は、窒化珪素の耐摩耗性が悪い原因について
種々検討した結果、以下の知見を発見して本発明を完成
したものである。The present inventor has completed the present invention by finding the following findings as a result of various studies on the cause of poor wear resistance of silicon nitride.

即ち、被削材又は相手材のほとんどは鉄系の合金が多
く、これに対して窒化珪素の主構成元素であるSiは化学
的親和性が高いために、耐摩耗性が劣ることを見出し
た。ここで、窒化珪素の焼結は、従来より窒化珪素の分
解揮発を防ぐ工夫がなされていた。本発明は、逆にこの
分解揮発を利用し、表面部の窒化珪素成分のSi含有量の
内部に対する減少率を20重量％（以下、単に％という）
以上とした窒化珪素基焼結体が、靱性等を低下させるこ
となく耐摩耗性を向上させるという知見を得た。That is, most of the work material or the counterpart material has many iron-based alloys, whereas Si, which is the main constituent element of silicon nitride, has a high chemical affinity, and thus has poor wear resistance. . Here, the sintering of silicon nitride has conventionally been devised to prevent decomposition and volatilization of silicon nitride. On the contrary, the present invention utilizes the decomposition and volatilization to reduce the silicon content of the silicon nitride component on the surface to the inside by 20% by weight (hereinafter simply referred to as%).
It has been found that the silicon nitride-based sintered body described above improves wear resistance without lowering toughness and the like.

即ち、特許請求の範囲第１項記載の窒化珪素基焼結体
は、上記のように、成形体から焼結体を得る過程におい
て表面の窒化珪素が分解揮発されていることにより、表
面部と内部ではそれを構成するSi含有量が異なることを
特徴とする。That is, as described above, the silicon nitride-based sintered body according to claim 1 has a structure in which silicon nitride on the surface is decomposed and volatilized in the process of obtaining the sintered body from the molded body, so that It is characterized in that the Si content constituting the inside is different.

また、特許請求の範囲第２項記載の窒化珪素基焼結体
の製造方法は、原料粉末の成形体から焼結体を得る過程
において表面の窒化珪素を分解揮発させることにより、
表面部と内部ではそれを構成するSi含有量は異なる焼結
体を得ることを特徴とする。In addition, the method for producing a silicon nitride-based sintered body according to claim 2 is characterized in that silicon nitride on the surface is decomposed and volatilized in a process of obtaining a sintered body from a compact of the raw material powder,
It is characterized in that sintered bodies having different Si contents constituting the surface portion and the inside are obtained.

ここで、上記Si減少率は、上記特許請求の範囲欄で述
べた式により算出される。この減少率を20％とするの
は、20％未満ではその効果が十分でなく、それ以上の場
合は靱性等に優れるという内部の特性を低下させること
なく耐摩耗性を向上させることができるからである。
尚、この減少率は50％以上が好ましい。この場合は耐摩
耗性が一層向上するからである。また、表面部のSi含有
量がほとんどなくなってもよく、この場合は耐摩耗性が
より一層向上するが、面粗度が低下するので、脆い化合
物が生成しない範囲にするのが好ましい。Here, the Si reduction rate is calculated by the equation described in the claims. The reason why the reduction rate is set to 20% is that if it is less than 20%, the effect is not sufficient, and if it is more than 20%, the wear resistance can be improved without lowering the internal characteristics such as excellent toughness and the like. It is.
Incidentally, this reduction rate is preferably 50% or more. In this case, the wear resistance is further improved. In addition, the Si content in the surface portion may be almost eliminated. In this case, the abrasion resistance is further improved, but the surface roughness is reduced, so that it is preferable that the brittle compound is not generated.

本窒化珪素基焼結体は通常、窒化珪素を主体とするも
のであるが、これに限らずサイアロンであってもよい。
この窒化珪素又はサイアロンとしても、α−、β型を問
わず、目的、用途により選択され、更にそれらの混合で
あってもよい。窒化珪素等以外の成分としては、粒界相
構成成分又は粒界相以外の第３成分とすることができ
る。粒界相構成成分は、ガラス相のみであってもよい
し、ガラス相以外に種々の結晶相を含んでもよい。第３
成分としては、例えば耐摩耗性、靱性向上に有効な成分
とすることができる。このものとしては、例えば、周期
律表第IVa、Va、VIa族遷移金属の炭化物、窒化物及び酸
化物、並びにこれら２種以上の固溶体のうちの１種若し
くは２種以上等を用いることができる。尚、この化合物
は、焼結体の靱性を低下させないために、30重量％以下
が好ましい。The present silicon nitride-based sintered body is usually mainly composed of silicon nitride, but is not limited thereto, and may be sialon.
This silicon nitride or sialon may be selected depending on the purpose and application irrespective of α- or β-type, and may be a mixture thereof. As components other than silicon nitride and the like, a grain boundary phase constituent component or a third component other than the grain boundary phase can be used. The component of the grain boundary phase may be a glass phase alone or may include various crystal phases in addition to the glass phase. Third
The component can be, for example, a component effective for improving wear resistance and toughness. As this, for example, carbides, nitrides and oxides of transition metals of Groups IVa, Va and VIa of the periodic table, and one or more of these two or more solid solutions can be used. . Incidentally, this compound is preferably at most 30% by weight so as not to lower the toughness of the sintered body.

内部とは、表面部を除いた部分であり、本窒化珪素基
焼結体の主要部となり、本焼結体の本質的特性を示す部
分である。この内部は、Si3N4が分解揮発除去（以下、
気化という）されないので、上記窒化珪素等及び粒界構
成成分更には上記第３成分がそのままで構成される。The term “inside” refers to a portion excluding the surface portion, is a main portion of the present silicon nitride-based sintered body, and is a portion exhibiting essential characteristics of the present sintered body. Inside this, Si 3 N 4 is decomposed and volatilized (hereinafter, referred to as
Therefore, the above-mentioned silicon nitride and the like, the components constituting the grain boundaries, and the third component are formed as they are.

表面部は、Si3N4が気化されてSi含有量が減少した
分、Si3N4以外の成分が残存し、その成分の相対的含有
率が向上した部分である。表面部の厚さは、目的、用途
及び製造方法等により異なるが、通常、数μｍ〜0.1mm
程度である。尚、本焼結体においては、表面部と内部の
境界において上記組成比が急に変わらない場合即ち連続
的に変わる場合も含まれ、このように少なくとも所定の
組成比をもつ表面部と所定の組成比をもつ内部とをもつ
ものであればよい。Surface portions, Si 3 N 4 min the Si content is vaporized is decreased, and the residual components other than Si 3 N 4, a part with improved relative content of the components. The thickness of the surface portion varies depending on the purpose, application, manufacturing method, etc.
It is about. In the present sintered body, the case where the composition ratio does not change abruptly at the boundary between the surface portion and the inside, that is, the case where the composition ratio changes continuously is also included. Thus, at least the surface portion having the predetermined composition ratio and the predetermined What is necessary is just to have the inside which has a composition ratio.

本焼結体は表面のSi3N4分を気化させた焼肌にて通常
使用されるので、気化に伴う面粗度の悪化には注意をす
る必要がある。従って、この面粗度は12.5S（JIS B 060
1）以下にするのが好ましい。特に、面粗度を重視する
用途の場合は、粒界相形成成分が残留し表面を覆うのが
好ましい。Since this sintered body is generally used on a burnt surface in which Si 3 N 4 components on the surface are vaporized, it is necessary to pay attention to the deterioration of the surface roughness due to the vaporization. Therefore, this surface roughness is 12.5S (JIS B 060
1) Preferably, In particular, when the surface roughness is important, it is preferable that the components forming the grain boundary phase remain and cover the surface.

本焼結体は、通常、一般的な常圧焼結法により製造さ
れるが、ガス圧焼結法又は熱間静水圧焼結法（HIP法）
により製造することもできる。焼成雰囲気は、基本的に
は窒素を含有した雰囲気で行うことが必要で、圧力は窒
化珪素が適当量気化する条件であればよく、減圧から数
千気圧まで変化させることができる。焼結温度は、通
常、1550〜1800℃の範囲を用い、好ましくは1600〜1750
℃である。This sintered body is usually manufactured by a general normal pressure sintering method, but a gas pressure sintering method or a hot isostatic sintering method (HIP method)
Can also be produced. The firing atmosphere basically needs to be performed in an atmosphere containing nitrogen, and the pressure may be a condition under which silicon nitride is vaporized in an appropriate amount, and can be changed from reduced pressure to several thousand atmospheres. The sintering temperature is usually in the range of 1550 to 1800 ° C, preferably 1600 to 1750.
° C.

本焼結体の製造方法は、例えば、まず、窒化珪素粉
末、所定の焼結助剤等を所定組成に配合し、混合、粉砕
する。焼結助剤としては、窒化珪素の常圧焼結（ガス圧
焼結、HIP焼結も含む）用の助剤であればよく、好まし
くはSi元素を含まないものがよい。このものとして、例
えば、Al2O3、Y2O3、AIN、MgO若しくはCaO、又はY2O3等
の希土類酸化物等がある。この素地は、必要形状に加圧
成形されて、特許請求の範囲第３項に記載のようにSi含
有量が全体にわたって均一である成形体となり、この成
形体を焼結することにより焼結体が得られる。この成形
体から焼結体を得る過程おいて、表面のSi3N4を気化さ
せる方法としては、例えば、窒素分圧、Si分圧を下げた
り、還元雰囲気を用いたりすることができる。In the method for manufacturing the present sintered body, for example, first, silicon nitride powder, a predetermined sintering aid, and the like are blended in a predetermined composition, mixed, and pulverized. The sintering aid may be an auxiliary for normal pressure sintering of silicon nitride (including gas pressure sintering and HIP sintering), and preferably does not contain Si element. For example, there are rare earth oxides such as Al 2 O 3 , Y 2 O 3 , AIN, MgO or CaO, or Y 2 O 3 . The green body is pressure-formed into a required shape to form a green body having a uniform Si content throughout as described in claim 3, and the green body is sintered by sintering the green body. Is obtained. As a method of vaporizing Si 3 N 4 on the surface in the process of obtaining a sintered body from the molded body, for example, a nitrogen partial pressure, a Si partial pressure can be reduced, or a reducing atmosphere can be used.

尚、上記「成形体から焼結体を得る過程」は仮焼段階
を含んでもよい。ただし通常、表面のSi3N4の気化は焼
結段階において行われる。In addition, the above-mentioned "process of obtaining a sintered body from a molded body" may include a calcining step. However, the vaporization of the surface Si 3 N 4 is usually performed during the sintering stage.

〔実施例〕〔Example〕

以下、実施例により本発明を具体的に説明する。 Hereinafter, the present invention will be described specifically with reference to examples.

まず、原料粉末として、平均粒径0.6μｍのSi3N4（α
化率90容積％以上）粉末、同0.5μｍのAl2O3若しくはMg
O、同1.3μｍのAlN粉末、同1.2μｍのY2O3粉末、同0.4
μｍのZrO2粉末、同1.2μｍのTiN粉末、同1.7μｍのHfN
粉末、同2.0μｍのWC粉末を、各々表に示す配合組成に
配合し、湿式ボールミルで48時間混合した後、成形助剤
を添加して乾燥した。First, as raw material powder, Si 3 N 4 (α
Powder, 0.5 μm Al 2 O 3 or Mg
O, 1.3 μm AlN powder, 1.2 μm Y 2 O 3 powder, 0.4 μm
μm ZrO 2 powder, 1.2 μm TiN powder, 1.7 μm HfN
The powder and the WC powder of 2.0 μm each were blended in the composition shown in the table, mixed by a wet ball mill for 48 hours, and then dried by adding a molding aid.

この粉末を用いて金型成形し、1650〜1750℃、窒素圧
0.7〜10気圧、一部は炭酸ガスを併用した雰囲気中で焼
成して焼結体を製造した。尚、表面部の厚さは、研削に
よる表面削除及び微小領域Ｘ線回折により測定した所、
いずれも約0.01〜0.1mm程度であった。Molding using this powder, 1650 ~ 1750 ℃, nitrogen pressure
The sintered body was manufactured by firing at 0.7 to 10 atm, partly in an atmosphere using carbon dioxide gas. The thickness of the surface portion was measured by surface removal by grinding and X-ray diffraction in a minute area.
Each was about 0.01 to 0.1 mm.

この焼結体は、SNMN432（JIS B4103）の寸法に仕上げ
た。但し、この仕上加工は、上下面のみ研削加工を行い
側面は焼肌のままとし、これをテストピース（チップ）
２とした。その寸法はプレス成形時に調整した。以下に
示す３つの方法による評価（特に方法１、２は耐摩耗
性、方法３は強度）を行い、その結果を表及び第１図に
示した。This sintered body was finished to the dimensions of SNMN432 (JIS B4103). However, in this finishing process, only the upper and lower surfaces are ground and the side surfaces remain as burnt skin, and this is used as a test piece (chip)
And 2. Its dimensions were adjusted during press molding. Evaluation was performed by the following three methods (particularly, methods 1 and 2 were abrasion resistance, and method 3 was strength). The results are shown in the table and FIG.

方法１、２、３の各条件は以下の通りである。尚、方
法２は小括弧内、方法３は中括弧内に示した。また、方
法１における寿命は、以下に述べるように欠損までの時
間をとっている。この場合、欠損の主因は単純な機械的
強度ではなく、摩耗により切削抵抗が増大した結果であ
り、耐摩耗性の目安として使われる。The conditions of the methods 1, 2, and 3 are as follows. Note that Method 2 is shown in parentheses and Method 3 is shown in curly brackets. In addition, the life in the method 1 is the time until the defect as described below. In this case, the main cause of the defect is not a simple mechanical strength but a result of an increase in cutting resistance due to wear, which is used as a measure of wear resistance.

被削材；インコネル718（FC20）［FC23］ 切削速度（m/分）;250（600）［150］ 切込み（mm）;1（0.5）［２］ 送り（mm/rev）;0.25（0.2）［0.6］ 切削油；水溶性油（なし）〔なし〕 切削時間（秒）；欠損まで（330）〔欠損まで〕 寿命判定；秒（mm）［山数〕 被削材（図中の１）形状；第２図に示すように外径30
0mmφ、内径200mmφのドーナツ状（第３図に示すように
外径240mmφの棒状）〔第４図に示すように外径240mm
φ、山幅15mmのリング状溝付き棒状〕。Work material: Inconel 718 (FC20) [FC23] Cutting speed (m / min); 250 (600) [150] Depth of cut (mm); 1 (0.5) [2] Feed (mm / rev); 0.25 (0.2) [0.6] Cutting oil; water-soluble oil (none) [none] Cutting time (seconds): Until chipping (330) [until chipping] Life judgment: seconds (mm) [number of peaks] Work material (1 in the figure) Shape; outer diameter 30 as shown in FIG.
Donut shape with 0 mmφ and inner diameter of 200 mmφ (rod shape with outer diameter of 240 mmφ as shown in FIG. 3) [240 mm outer diameter as shown in FIG. 4
φ, ring-shaped grooved rod with a peak width of 15 mm].

尚、図中の３はホルダーを示す。方法２の寿命判定は
側面側の摩耗によった。In addition, 3 in a figure shows a holder. The life determination in Method 2 was based on the side wear.

Si3N4（サイアロンも含む）は使用目的に応じてその
配合組成等は決定される。従って同一条件下でこれらの
例を比較することが困難である。例えば、上記比較例に
おいて、比較的高強度の型（比較例１）、比較的Ni合金
に適した型（比較例２）、比較的鋳物に適した型（比較
例３）を示しており、これらの型を相 互に比較することはほとんど意味がなく、各型内での比
較が意味がある。従って、表には、同一又は類似の原料
配合組成間にて性能を比較できるように配列し、その結
果を述べると以下の通りである。尚、比較例１、３の各
々は、各実施例１、６の各々を研削加工してその表面か
ら約0.2mm以上削除し、表面部を完全に除去して内部を
表出させたものである。比較例２は実施例３の組成で表
面のSiがほとんど減少していない焼肌をもつものであ
る。The composition and the like of Si 3 N 4 (including sialon) are determined according to the purpose of use. Therefore, it is difficult to compare these examples under the same conditions. For example, in the comparative example, a relatively high-strength mold (Comparative Example 1), a mold relatively suitable for Ni alloy (Comparative Example 2), and a mold relatively suitable for casting (Comparative Example 3) are shown. These types It makes little sense to compare each other, and it makes sense to compare within each type. Therefore, the table is arranged so that the performance can be compared between the same or similar raw material composition, and the results are as follows. Each of Comparative Examples 1 and 3 was obtained by grinding each of Examples 1 and 6 to remove about 0.2 mm or more from the surface, completely removing the surface portion, and exposing the inside. is there. Comparative Example 2 has a burnt surface of the composition of Example 3 with almost no decrease in Si on the surface.

表面部のSi含有量を減らした各実施例を各比較例と比
べると（実施例１と比較例１、実施例３と比較例２、実
施例６〜８と比較例３）、いずれも耐摩耗性が向上して
いる。この場合、いずれも強度は若干低下するがほとん
ど変わらず、問題となる程度のものではない。更に、実
施例６〜８及び比較例３において、Si減少率と耐摩耗性
の関係を第１図に示すと、その減少率が大きくなるに従
って耐摩耗性が向上しており、特にそれが20％以上では
その効果に優れる。Comparing each of the examples in which the Si content of the surface portion was reduced with each of the comparative examples (Example 1 and Comparative Example 1, Example 3 and Comparative Example 2, and Examples 6 to 8 and Comparative Example 3). Abrasion is improved. In this case, in all cases, the strength slightly decreases, but hardly changes, and is not a problematic degree. Further, in Examples 6 to 8 and Comparative Example 3, the relationship between the Si reduction ratio and the wear resistance is shown in FIG. 1. As the reduction ratio increases, the wear resistance improves. %, The effect is excellent.

また、これらにIVa、VIa族遷移金属の化合物（HfN、W
C、TiN）を配合したもの（実施例２、４、６）は配合し
ないもの（実施例１、３、５）と比べると、耐摩耗性は
改善される。尚、この配合量があまり多いと、実施例９
のように強度がかなり低下する場合があるので注意する
必要がある。In addition, compounds of IVa and VIa group transition metals (HfN, Wf
(A, C, TiN) (Examples 2, 4, and 6) have improved abrasion resistance as compared with those without (C, TiN) (Examples 1, 3, and 5). In addition, when this blending amount is too large, Example 9
It should be noted that the strength may decrease considerably as in

以上より、実施例１〜９については、表面部のSi減少
率が25〜61％であるので、いずれも強度を維持しつつ耐
摩耗性が向上しており、表面部及び内部を構成する材料
の特性を十分に発揮できた。As described above, in Examples 1 to 9, the reduction rate of Si in the surface portion was 25 to 61%, so that the abrasion resistance was improved while maintaining the strength, and the material constituting the surface portion and the inside was used. The characteristic of was fully demonstrated.

〔発明の効果〕〔The invention's effect〕

本発明の窒化珪素基焼結体は、成形体から焼結体を得
る過程において表面の窒化珪素が分解揮発されているこ
とによりその表面部のSi含有量が内部と比べて20％以上
減少しており、その内部はSi3N4の気化がなくそのまま
であるので、表面部の耐摩耗性に優れるという性質と内
部の高靱性等という本質的特性が十分に発揮される。即
ち、本焼結体は、従来のように両性質の中間的特性を示
すものではない。従って、本焼結体では、その表面改質
により、内部の本質的特性を低下させることなく耐摩耗
性を向上させることができる。また、表面部と内部は一
体のため、両者間の接合強度が高く剥離することもな
い。In the silicon nitride based sintered body of the present invention, the silicon content on the surface is decomposed and volatilized in the process of obtaining the sintered body from the molded body, so that the Si content on the surface is reduced by 20% or more compared with the inside. Since Si 3 N 4 is not vaporized inside, the essential properties such as excellent wear resistance of the surface portion and high toughness of the inside are sufficiently exhibited. That is, the present sintered body does not show an intermediate property between the two properties as in the related art. Therefore, in the present sintered body, the wear resistance can be improved without deteriorating the internal essential characteristics by the surface modification. Further, since the surface portion and the inside are integrated, the bonding strength between the two is high and there is no peeling.

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

第１図は表面部のSi減少率と耐摩耗性の関係を示すグラ
フ、第２図は方法１に用いた被削材形状等を示す説明断
面図、第３図は方法２に用いた被削材形状等を示す説明
断面図、第４図は方法３に用いた被削材形状等を示す一
部断面図である。 1;被削材、2;窒化珪素基焼結体チップ、3;ホルダー。FIG. 1 is a graph showing the relationship between the Si reduction rate of the surface portion and wear resistance, FIG. 2 is an explanatory sectional view showing the shape of the work material used in Method 1, and FIG. FIG. 4 is a partial sectional view showing the shape of the work material used in the method 3 and the like. 1; work material; 2; silicon nitride-based sintered body chip; 3; holder.

Claims (3)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】成形体から焼結体を得る過程において表面
の窒化珪素が分解揮発されていることにより、内部のSi
含有量に対する表面部のSi含有量の以下の算出式に示す
減少率が、20重量％以上であることを特徴とする窒化珪
素基焼結体。 Si減少率＝［｛内部Si含有量（重量）−表面部Si含有量
（重量）｝／内部Si含有量（重量）］×100。(1) In the process of obtaining a sintered body from a molded body, the internal silicon nitride is decomposed and volatilized, so that the internal Si
A silicon nitride-based sintered body, characterized in that the reduction rate of the Si content of the surface portion with respect to the content shown in the following calculation formula is 20% by weight or more. Si reduction rate = [{internal Si content (weight) −surface Si content (weight)} / internal Si content (weight)] × 100. 【請求項２】原料粉末を成形し、この成形体から焼結体
を得る過程において表面の窒化珪素を分解揮発させるこ
とにより、内部のSi含有量に対する表面部のSi含有量の
以下の算出式に示す減少率が20重量％以上である焼結体
を得ることを特徴とする窒化珪素基焼結体の製造方法。 Si減少率＝［｛内部Si含有量（重量）−表面部Si含有量
（重量）｝／内部Si含有量（重量）］×100。2. The following formula is used to decompose and volatilize silicon nitride on the surface in the process of forming a raw material powder and obtaining a sintered body from the formed body, thereby calculating the Si content of the surface with respect to the internal Si content. A method for producing a silicon nitride-based sintered body, characterized by obtaining a sintered body having a reduction rate of 20% by weight or more as shown in (1). Si reduction rate = [{internal Si content (weight) −surface Si content (weight)} / internal Si content (weight)] × 100. 【請求項３】上記成形体は、成形時におけるSi含有量が
全体にわたって均一である、特許請求の範囲第２項記載
の窒化珪素基焼結体の製造方法。3. The method for producing a silicon nitride-based sintered body according to claim 2, wherein said molded body has a uniform Si content during molding.
JP63306320A 1988-12-03 1988-12-03 Silicon nitride sintered body and method for producing the same Expired - Fee Related JP2719942B2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP63306320A JP2719942B2 (en) 1988-12-03 1988-12-03 Silicon nitride sintered body and method for producing the same
DE3939989A DE3939989C2 (en) 1988-12-03 1989-12-02 Method for producing a sintered body based on silicon nitride and sintered body based on silicon nitride
KR1019890017810A KR960016069B1 (en) 1988-12-03 1989-12-02 Silicon nitride base sintered body
US08/075,917 US5316856A (en) 1988-12-03 1993-06-14 Silicon nitride base sintered body

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63306320A JP2719942B2 (en) 1988-12-03 1988-12-03 Silicon nitride sintered body and method for producing the same

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JPH02153865A JPH02153865A (en) 1990-06-13
JP2719942B2 true JP2719942B2 (en) 1998-02-25

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DE4025239C1 (en) * 1990-08-09 1991-12-19 Hoechst Ceramtec Ag, 8672 Selb, De
DE4038003C2 (en) * 1990-11-29 1997-01-02 Bayer Ag Process for the production of sintered materials based on Si¶3¶N¶4¶
DE19859591A1 (en) * 1998-12-22 2000-06-29 Kennametal Inc Functional gradient sintered ceramic body, especially a cutter plate or insert for metal machining, is produced from silicon nitride powder containing a magnesium, titanium, zirconium, hafnium and-or yttrium oxide mixture
US6610113B1 (en) 1999-09-09 2003-08-26 Kennametal Pc Inc. Process for heat treating ceramics and articles of manufacture made thereby

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DE2800174A1 (en) * 1978-01-03 1979-07-12 Max Planck Gesellschaft PROCESS FOR SINTERING SILICON NITRIDE SHAPED BODIES
DE2940629A1 (en) * 1979-10-06 1981-04-16 Daimler-Benz Ag, 7000 Stuttgart METHOD FOR PRODUCING OXIDATION-RESISTANT SILICON NITRIDE SINTER BODIES WITH IMPROVED MECHANICAL STRENGTH
US4400427A (en) * 1981-12-21 1983-08-23 Gte Laboratories Incorporated Sintered silicon nitride ceramic articles having surface layers of controlled composition
DE3216308A1 (en) * 1982-04-30 1983-11-03 Feldmühle AG, 4000 Düsseldorf Sintered moulding based on silicon nitride
JPS6011288A (en) * 1983-06-30 1985-01-21 三菱マテリアル株式会社 Surface coated sialon-base ceramic tool member
SE451581B (en) * 1984-04-06 1987-10-19 Sandvik Ab CERAMIC MATERIAL MAINLY BASED ON SILICON NITRIDE, ALUMINUM NITRIDE AND ALUMINUM OXIDE
JPS6140871A (en) * 1984-07-25 1986-02-27 住友電気工業株式会社 Solderable si3n4 ceramic composite composition and manufacture
JPS631278A (en) * 1986-06-20 1988-01-06 Matsushita Electric Ind Co Ltd Color solid-state image pickup device
JPS63190786A (en) * 1987-01-30 1988-08-08 日立金属株式会社 Coated silicon nitride base ceramics and manufacture

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DE3939989A1 (en) 1990-07-05
KR900009499A (en) 1990-07-04
JPH02153865A (en) 1990-06-13
DE3939989C2 (en) 1994-08-11
KR960016069B1 (en) 1996-11-27

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