CN1908214A

CN1908214A - Preparation method of titanium carbosilicide based gradient material and in situ reaction

Info

Publication number: CN1908214A
Application number: CN 200610030080
Authority: CN
Inventors: 王连军; 张建峰; 江莞; 陈立东
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2006-08-16
Filing date: 2006-08-16
Publication date: 2007-02-07
Anticipated expiration: 2026-08-16
Also published as: CN100455688C

Abstract

the invention discloses a Ti carbon silica gradient material and preparing method of original reaction, which comprises the following steps: preparing one end of gradient material as single-phase Ti3SiC2 and the other end as Ti3SiC2-TiC or SiC-TiC phase with at least one layer in the middle; selecting Ti, Si, C and Al as raw material; sintering after blending with discharging plasma at 1200-1500 deg.c; heating at 80-200 deg.c /min; setting pressure at 50-70Mpa; keeping temperature for 6-10 min.

Description

The preparation method of carbon titanium silicide based gradient material and reaction in

Technical field

The present invention relates to the preparation of gradient ceramic, relate to carbon titanium silicide (Ti or rather ₃SiC ₂) method of based gradient material and reaction in preparation.

Background technology

Carbon titanium silicide (Ti ₃SiC ₂) material has some excellences of Ceramic-to-Metal concurrently and particular performances, for example specific conductivity is 2 times of metal Ti, and has high thermal, can also have enough resistance of oxidation up to 1100 ℃.Ti ₃SiC ₂Crystal grain trend forms unique laminate structure district, and may take place normal temperature under that crystal grain is extracted, crystal grain is passed and microplasticity is out of shape the homenergic mechanism of absorption and has high toughness, is generally 8-16MPam ^1/2Ti ₃SiC ₂Body material room temperature bending strength is 300-600MPa.On the other hand, Ti ₃SiC ₂The low 6GPa of the hardness of material belongs to soft pottery, and this makes it can carry out more cheap turning processing.But, Ti ₃SiC ₂Poor at the high temperature resistant property more than 1100 ℃; Simultaneously because its hardness is not high, so its wear resistance can be poor.Carbon titanium silicide (Ti ₃SiC ₂) the existing multinomial patent of preparation method of monophase materials, as ZL98114247.8, ZL98114365.2 etc.

Silicon carbide (SiC) belongs to the very strong compound of covalent bonds, the hardness height, and the hot strength height, resistance toheat surmounts other pottery, has good oxidation-resistance simultaneously.Therefore, obtained widespread use as non-oxide ceramic material at refractory materials, abrasive, exothermic material etc.Titanium carbide (TiC) is typical transition metal carbide, belongs to face-centred cubic NaCl type structure, and its crystalline structure has determined TiC to have essential characteristics such as high-melting-point, high rigidity, wear-resisting and conduction.Therefore TiC can be used for preparing cutting tool, but single-phase TiC poor toughness, can add second usually and prepares matrix material mutually in order to improve its toughness, for example the TiC/SiC matrix material.SiC and TiC have high rigidity, so difficult processing.The researchist once joined Ti with SiC or TiC ₃SiC ₂In, improved Ti ₃SiC ₂The hardness of material and, wear resisting property and oxidation-resistance or the like performance, but lost Ti ₃SiC ₂The processability of material.

Inventor's imagination is with Ti ₃SiC ₂, materials such as SiC, TiC advantages get up, utilize the SPS reaction in to prepare carbon titanium silicide (Ti ₃SiC ₂) based gradient material.Prepared material one end of the present invention is single-phase Ti ₃SiC ₂Material, the other end are Ti ₃SiC ₂/ SiC or SiC/TiC matrix material, make material not only firmly but also soft, one end is beneficial to machine-shaping, the other end has high rigidity, characteristics such as wear-resisting, anticorrosive, anti-oxidant, can be applied to fields such as space flight and aviation, chemical industry, machinery, metallurgy, nuclear industry, and characteristics such as preparation cycle is short, energy consumption is low, environmental friendliness have wide commercial application prospect.

Summary of the invention

The object of the present invention is to provide a kind of carbon titanium silicide (Ti of reaction in preparation ₃SiC ₂) basic gradient composite diphase material and method, it is characterized in that the prepared material of the present invention one end is single-phase Ti ₃SiC ₂Material, the other end are Ti ₃SiC ₂/ SiC or SiC/TiC matrix material are not only soft but also hard.

Key problem in technology of the present invention is that by selecting Ti, Si, C powder and Al powder be that raw material, design raw material are formed proportioning, optimized processing parameter, the control microstructure develops, and has meticulous microstructure to obtain, favorable conductive and a mechanical property sintered material.The purpose of adding Al is to eliminate generation Ti ₃SiC ₂The time TiC impurity that exists.Addition＜3wt% of Al, the actual 0.1-2wt% of being is advisable.At first design raw material and form proportioning, pass through traditional mechanical batch mixing then, carry out SPS reaction in sintering at last, main by control SPS sintering process parameter, comprise sintering temperature, pressure, temperature rise rate, soaking time etc.Following each step is specifically arranged:

1, the selection of material powder and preparation

With commercially available commercial Ti, Si, C powder and trace of Al powder is raw material, according to Ti ₃SiC different volumes content design proportioning is carried out the weighing of material powder, and the weight of powder is the density that multiply by every layer component by required every layer thickness, and this density is calculated (seeing embodiment for details) by adding with theorem.Utilize mechanical ball milling to carry out batch mixing then.The ball mill mixing process generally adopts the silicon carbide abrading-ball, and rotational speed of ball-mill is that 200～250rpm, ball material weight ratio are that 4: 1, ball milling time are 20-24h.Carry out drying at last, sieving obtains the raw material mixed powder.

2, discharge plasma quick in situ reaction sintering (SPS)

This process is at vacuum condition or Ar or N ₂Carry out under the protective atmosphere, select different graphite gradient moulds for use according to graded.In preparation process, need strict control process parameters, comprise sintering temperature, pressure, temperature rise rate, soaking time etc.Wherein, sintering temperature and temperature rise rate are regulated by the size of pulsed current and voltage.Reaction in agglomerating temperature range is 1200～1500 ℃; Being incubated 6-10 minute temperature rise rate scope is 80～200 ℃/min; According to definite concrete whole sintering times such as the different initial particle size of powder, be generally 15～30min; Pressure range is 50～70Mpa, applies 5-10MPa pressure before reaching sintering temperature earlier, makes between powder to be in contact with one another.

The inventor once provided a kind of reaction in to prepare carbon titanium silicide (Ti ₃SiC ₂) method of based gradient material.Adopt common commercial powder, by the quick densifying reaction sintering with control microstructure, on the basis that guarantees material excellent mechanical performances and electroconductibility, utilization ratio, workability, the reliability of products of material are greatly improved, preparation cycle is short, energy consumption is low, environmental friendliness, production cost significantly reduces, thereby has good industrial prospect.

So-called graphite gradient mould is in order to adapt to SPS sintering needs particular design, its external diameter all is columniform, internal diameter then is trapezoidal, its objective is and have a temperature difference when making the SPS sintering, 20-30 ℃/cm of the hot-pressed material temperature difference involved in the present invention gets final product, this is because the electroconductibility of material is better, so have a narrow range of temperature, then also can meet the demands with isodiametric graphite jig.

Description of drawings

Fig. 1 is the X-ray diffractogram of embodiment 1;

Fig. 2 is the scanning electron microscope (SEM) of hard end material sintered compact fracture among the embodiment 1;

Fig. 3 is the changes in hardness relation of embodiment 1.

Embodiment

Embodiment 1

With three layers of graded is example, i.e. (Ti ₃SiC ₂)/(0.9Ti ₃SiC ₂-0.1SiC)/(0.8Ti ₃SiC ₂-0.2SiC).At first carry out proportion design, reaction equation is as follows:

0≤x＜1

Prepare burden according to design result then, Ti, Si, C powder and trace of Al powder are placed ball grinder, with alcohol medium ball milling wet mixing 24h, rotating speed is 250rpm, carries out drying and screening then.Dried powder is packed into behind the graphite jig by layer, put into SPS equipment and carry out sintering.

The SPS preparation process is carried out under vacuum condition, and sintering temperature is 1280 ℃; Temperature rise rate is 100～150 ℃/min; Soaking time is 6min; Adopt two step pressing mode, institute's applied pressure is 10MPa before the sintering, and holding stage institute applied pressure is 70MPa.The microhardness of the sintered compact that is obtained is 5～10GPa.

Embodiment 2

With three layers of graded is example, i.e. (Ti ₃SiC ₂)/(0.8Ti ₃SiC ₂-0.2SiC)/(0.7Ti ₃SiC ₂-0.3SiC).At first carry out proportion design, prepare burden according to design result then, Ti, Si, C powder and trace of Al powder are placed ball grinder, with alcohol medium ball milling wet mixing 20h, rotating speed is 250rpm, carries out drying and screening then.Powder is packed into behind the graphite jig by layer, put into SPS equipment and carry out sintering.

The SPS preparation process is carried out under vacuum condition, and sintering temperature is 1280 ℃; Temperature rise rate is 100～150 ℃/min; Soaking time is 6min; Adopt two step pressing mode, institute's applied pressure is 10MPa before the sintering, and holding stage institute applied pressure is 70MPa.The microhardness of the sintered compact that is obtained is 5～14GPa.

Embodiment 3

With four layers of graded is example, i.e. (Ti ₃SiC ₂)/(0.8Ti ₃SiC ₂-0.2SiC)/(0.7Ti ₃SiC ₂-0.3SiC)/(TiC-SiC).At first carry out proportion design, prepare burden according to design result then, Ti, Si, C powder and trace of Al powder are placed ball grinder, with alcohol medium ball milling wet mixing 24h, rotating speed is 250rpm, carries out drying and screening then.。Powder is packed into behind the graphite gradient mould by layer, put into SPS equipment and carry out sintering.Reaction equation is as follows:

0≤x≤1

And when x=1,

The SPS preparation process is at Ar, N ₂Or carry out under the vacuum condition, sintering temperature is 1280～1500 ℃; Temperature rise rate is 100 ℃/min; Soaking time is 10min; Adopt two step pressing mode, institute's applied pressure is 10MPa before the sintering, and holding stage institute applied pressure is 70MPa.The microhardness of the sintered compact that is obtained is 5～22GPa.

Claims

1, a kind of carbon titanium silicide based gradient material is characterized in that:

(1) prepared carbon titanium silicide base gradient phase material one end is single-phase Ti ₃SiC ₂, the other end is Ti ₃SiC ₂-TiC, the centre is one deck at least, satisfies chemical formula 0≤x＜1；

(2) prepared carbon titanium silicide based gradient material one end is single-phase Ti ₃SiC ₂, the other end is the SiC-TiC phase, the centre is one deck at least, satisfies chemical formula 0≤x≤1, and when x=1, 。

2, by the described carbon titanium silicide based gradient material of claim 1, it is characterized in that prepared carbon titanium silicide base gradient composite diphase material is Ti ₃SiC ₂/ 0.9Ti ₃SiC ₂-0.1SiC/0.8Ti ₃SiC ₂-0.2SiC.

3, by the described carbon titanium silicide based gradient material of claim 1, it is characterized in that described carbon titanium silicide base gradient composite diphase material is Ti ₃SiC ₂/ 0.8Ti ₃SiC ₂-0.2SiC/0.7Ti ₃SiC ₂-0.3SiC.

4, by the described carbon titanium silicide based gradient material of claim 1, it is characterized in that described carbon titanium silicide based gradient material is Ti ₃SiC ₂/ 0.8Ti ₃SiC ₂-0.2SiC/0.7Ti ₃SiC ₂-0.3SiC/TiC-SiC.

5, the reaction in method of preparation carbon titanium silicide based gradient material use as claimed in claim 1 is characterized in that:

(1) selecting Ti, Si, C powder and Al powder is raw material, presses chemical formula , 0≤x＜1 or press chemical formula , 0≤x≤1 and every layer thickness, the design proportioning, Al powder add-on is less than 3wt%;

(2) mechanical ball milling batch mixing, drying, sieving materials, rotational speed of ball-mill 200-250rpm; 20-24 hour ball milling time;

(3) discharge plasma sintering

With the powder of step (2) preparation, being placed on internal diameter is in the equal diameter graphite jig, and the reaction in sintering temperature is 1200-1500 ℃, and temperature rise rate is 80-200 ℃/min, and pressure is 50-70MPa;

6,, it is characterized in that described sintering temperature and temperature rise rate regulate by pulsed current and voltage swing by the preparation method of the described carbon titanium silicide based gradient material of claim 5 reaction in.

7, by the preparation method of the described carbon titanium silicide based gradient material of claim 5 reaction in, ball material weight ratio is 4: 1 when it is characterized in that ball milling.

8,, it is characterized in that before reaching sintering temperature, applying earlier the pressure of 5-10MPa by the preparation method of the described carbon titanium silicide based gradient material of claim 5 reaction in.

9, by the preparation method of the described carbon titanium silicide based gradient material of claim 5 reaction in, it is characterized in that the sintered heat insulating time is 6-10min.

10, by the preparation method of the described carbon titanium silicide based gradient material of claim 5 reaction in, it is characterized in that reaction in agglomerating atmosphere is vacuum or Ar or N ₂Protective atmosphere.