CN106376107B

CN106376107B - High-power silicon nitride ceramic heating plate and manufacturing method of high-power silicon nitride ceramic heating plate with soft inside and hard outside

Info

Publication number: CN106376107B
Application number: CN201611042278.0A
Authority: CN
Inventors: 肖毅
Original assignee: Changde Cree New Mstar Technology Ltd
Current assignee: Changde Cree New Mstar Technology Ltd
Priority date: 2016-11-24
Filing date: 2016-11-24
Publication date: 2020-03-20
Anticipated expiration: 2036-11-24
Also published as: CN106376107A

Abstract

The high-power silicon nitride ceramic heating piece and the manufacturing method of the high-power silicon nitride ceramic heating piece with soft inside and hard outside comprise an insulating ceramic plate, heating ceramic, welding ceramic and an external lead, and the manufacturing method comprises the following steps: firstly, carrying out ball milling on an insulating ceramic material, drying, adding an adhesive, drying and sieving; secondly, the insulating ceramic material is formed by cold pressing, drying, sintering and cutting; thirdly, respectively adding the heating ceramic powder and the welding ceramic powder into the adhesive, uniformly stirring, drying, granulating, forming, putting into an insulating ceramic blank body, and integrally pressing into a whole; fourthly, hardening and degumming the whole body; fifthly, sintering, hardening and forming. The invention has the advantages that: 1. the heating can be carried out quickly, and the temperature control is accurate. 2. The heat generation is very uniform and the heat loss is very low. 3. The three kinds of ceramics are mutually and uniformly solid-solution sintered into a whole, so that the quality is high, and the probability of problems is reduced. 4. The welding is very strong.

Description

High-power silicon nitride ceramic heating plate and manufacturing method of high-power silicon nitride ceramic heating plate with soft inside and hard outside

Technical Field

The invention relates to silicon nitride ceramics, in particular to a high-power silicon nitride ceramic heating plate and a manufacturing method of the high-power silicon nitride ceramic heating plate with soft inside and hard outside.

Background

The high-power silicon nitride ceramic heating plate is generally over 500W, and the unit area power is more than 50W/cm²。

The heat exchanger has the characteristics of light weight, small volume, high heating speed, high power, low heat consumption, high heat transfer efficiency, stability and no deformation at high temperature and the like, and is increasingly and widely used in various industries, particularly the electronic industry.

At present, the domestic preparation of the silicon nitride ceramic heating plate comprises the following 2 process methods:

the method comprises the following steps: the tungsten wire is bent into a spring shape, springs with different lengths are placed in silicon nitride materials according to different required resistances, and then the springs are compacted and sintered and then lead wires are welded. As shown in fig. 1.

The second method comprises the following steps: preparing a silicon nitride flat plate ceramic blank and tungsten paste which are subjected to tape casting, printing the tungsten paste on the silicon nitride flat plate blank in a screen printing mode to form a heating conductor, then coating a layer of ceramic blank, and sintering to obtain the ceramic. As shown in fig. 2.

Third, the patent No. 2012100471693 'silicon nitride heating plate and its making method' uses Si₃N₄The powder and the heating body powder are pressed into a whole and then sintered.

These three processes all have relatively serious disadvantages:

1: the heating sheet is made on the ceramic, mainly utilizes the ceramic to make the device with larger power and small heat loss on a smaller area, but the diameter of the used heating tungsten filament is generally very small, about phi 0.4-0.5mm, and the thin tungsten filament and the ceramic powder are sintered together, can not be well dissolved and are very easy to damage.

2: the ceramic sintering is polycrystalline and cannot have micro-pores, which can be seen under a high power microscope, and the tungsten filament is heated in the air and is very easy to become brittle and burn off, which is the main reason that the ceramic heating plate is easy to damage.

3: the particle shapes of the ceramic powder are different, and a thin tungsten wire with the diameter of about 0.4mm is sintered with the ceramic particles at high temperature and high pressure, so that the surface of the tungsten wire is seriously damaged, and the wire is very easy to break in long-term repeated use.

4. The heating sheet manufactured on the ceramic tape-casting substrate is a product which can not manufacture large power due to the degumming process, the ceramic is generally an alumina material, and the alumina material has poor thermal shock property and can only be manufactured with small power.

5: because the tungsten filament is a spring-shaped heating body which is wound into different lead lengths and is arranged in the ceramic powder, the lead dimension of the spring cannot be controlled very accurately, and the heating is not uniform.

6: when the tungsten wire spring is added into the ceramic powder, the process is complex, the human factor is large, the actual power change is large, and the control is difficult.

7: the tungsten filament is arranged in the ceramic, the area of the outlet end is small, the welding of the outlet wire is very difficult, and the infirm welding is the main reason of problems in the use process.

8: because the heating tungsten wire is in the ceramic body, the resistance is large in change, the power is unstable, and the heating is large in change.

9. In patent application 2012100471693 "silicon nitride heating sheet and method for manufacturing the same", there are two major disadvantages, one is that the composition of the body and the heating body is not reasonable; secondly, when the sleeve pressing molding is carried out, powder blanks of a heating area and a non-heating area in the body and the heating body are crushed, the area and the length are not easy to control, the length and the area of the heating area and the non-heating area in the product are inaccurate, and the two defects cause inaccurate resistance and inaccurate power and can not be produced in batches.

Disclosure of Invention

In order to overcome the defects of easy damage, uneven heating, difficult welding of outgoing lines, unstable power and the like of tungsten wires in the three methods, the invention provides a novel high-power silicon nitride ceramic heating plate and a manufacturing method of the heating plate with soft inside and hard outside.

The high-power silicon nitride ceramic heating sheet is characterized by comprising an insulating ceramic plate, heating ceramic, welding ceramic and an external lead, wherein the conducting ceramic arranged in a U shape is sintered on the central surface of the insulating ceramic plate, two ends of the conducting ceramic are connected with the welding ceramic, one surface of the welding ceramic is exposed on the insulating ceramic plate and is a welding surface, and the external lead is welded on the welding surface. The following sections are described as follows:

1. the heating ceramic is formed by mixing conductive metal powder and non-conductive non-metal powder, the effect of adjusting resistance is achieved by adjusting the ratio of the metal powder to the non-metal powder, and the designed heating power is achieved by electrifying and heating.

2. The insulating ceramic plate is an insulating composite ceramic with large heat capacity, high strength, thermal shock resistance and high thermal stability.

3. The ceramic is welded, electric energy is rapidly conducted to the heating ceramic, and the heating ceramic does not generate heat, so that the temperature of a wire outlet end is low, and safe wiring is realized.

4. And the metal wire is welded on the exposed surface of the welding ceramic by an external lead, so that the outgoing wire is firm and reliable.

The ceramic heating body of the high-power silicon nitride ceramic heating sheet is composed of three parts of ceramic materials with different proportions, and the ceramic heating body is prepared from the following components in percentage by weight:

1. insulating ceramic material: silicon nitride Si₃N₄91.5-94%; ytterbium oxide Y₂O₃1-3%; aluminum oxide Al₂O₃0.5-1.5%; 0.2 to 0.5 percent of magnesium oxide MgO; lanthanum sesquioxide La₂O₃0.5-1%; hafnium oxide HfO₂0.2-0.5 percent of aluminum nitride AlN, 0.5-2 percent of aluminum nitride AlN, and the weight of all the components is 100 percent.

2. Heating ceramic material of silicon nitride Si₃N₄40-50%, solid solution of titanium carbide and titanium nitride, Ti (C, N), 26-35%; the weight ratio of titanium carbide to titanium nitride in solid solution is 4: 6; 0.5 to 3 percent of molybdenum powder Mo; 0.5 to 1.0 percent of nano nickel Ni; 0.2 percent of niobium carbide CHNb; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; SiO silicon oxide₂0.1-0.2%; aluminum oxide Al₂O₃5-10%, the weight of all components is 100%.

3. Welding a ceramic material: 60-72% of titanium carbide TiC; silicon nitride Si₃N₄20-30%; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; aluminum oxide Al₂O₃5-10%; SiO silicon oxide₂0.1-0.2%, the weight of all components is 100%.

The manufacturing method of the high-power silicon nitride ceramic heating chip with soft inside and hard outside is characterized by comprising the following steps:

firstly, the insulating ceramic material is respectively made of nylon tank and silicon nitride Si₃N₄Ball milling is carried out on the balls, drying is carried out for 72 hours after the ball milling to ensure that the water content is less than 1%, a pollution-free stirrer is used for mixing materials, a binding agent polyethylene glycol (PEG) is added during the mixing, the weight of the PEG accounts for 1-1.5% of the weight of the insulating ceramic material, and the mixture is dried and sieved by a 60-mesh sieve for later use;

secondly, using a special die manufactured according to the requirements of customer parts to form the insulating ceramic material by using cold isostatic pressing CIP, drying the insulating powder ceramic blank, putting the insulating powder ceramic blank into an air pressure sintering furnace for GPS sintering, and cutting the insulating powder ceramic blank into a required shape by a laser cutting machine for later use;

adding polyethylene glycol (PEG) adhesive in an amount which is 1-1.5% of the weight of the heating ceramic powder and the welding ceramic powder respectively, uniformly stirring, drying, granulating, forming into sheets by Cold Isostatic Pressing (CIP), respectively molding by using special molds, then putting into an insulating ceramic blank, and integrally pressing;

fourthly, hardening and degumming the whole body;

fifthly, putting the mixture into a hot isostatic pressing sintering furnace, sintering, reinforcing, hardening and forming, wherein the maximum sintering temperature is 1800-1820 ℃, and the pressure is as follows: 1500 MPa.

The composite processing and forming method is commonly called as: and (5) inner softening and outer hardening.

The high-power silicon nitride ceramic heating plate has the advantages that:

1. the bulk density is 3.4-3.6g/cm³In which the ceramic density is heated<5 g/cm³Density of insulating ceramics<3.25 g/cm³The ceramic heating plate has low density and low thermal capacity, can be quickly heated, needs less than 10 seconds when reaching 1000 ℃, is accurately controlled in temperature, and provides a good condition for automatic temperature control.

2. The heating ceramic is sintered into a polycrystalline structure, the heating is very uniform, and the heat loss is very low.

3. The heating ceramic, the insulating ceramic and the welding ceramic are uniformly solid-solution sintered into a whole, so that an interface is avoided, the quality of the heating sheet is greatly improved, and the probability of problems is reduced.

4. Because the welding end of the welding ceramic outgoing line is rectangular, the welding surface is large, and the general size is 3X1.5mm, the welding outgoing line is very firm.

5. The electric heater emits infrared long wave radiation heat transfer outwards, and the radiation coefficient of the heating ceramic is more than 0.9. The radiation coefficient of the tungsten wire is only 0.04, and the radiation heat is obviously small.

6. During sintering, the interfaces of the insulating ceramic, the heating ceramic and the welding ceramic are clear, but the insulating ceramic, the heating ceramic and the welding ceramic can be properly infiltrated mutually, and the resistance is stable and accurate.

Drawings

FIG. 1 is a structural view of a conventional ceramic heating sheet I

FIG. 2 is a structural view of a conventional ceramic heating plate II

FIG. 3 is a structural view of a ceramic heating sheet according to the present invention

In fig. 1: 1. silicon nitride ceramics, 2, tungsten wire springs, 3, tungsten wires, 4, welding ceramics, 5 and external connecting wires;

in fig. 2: 1. tungsten slurry, 2, a ceramic green body;

in fig. 3: 1. insulating ceramic, 2, conductive ceramic, 3, welding ceramic, 4, a welding surface, 5 and an external lead.

Detailed Description

The present invention is described in detail below by way of specific embodiments:

such a high power silicon nitride ceramic heater chip is shown in fig. 3. Three product descriptions for laboratory manufacturing are now exemplified. The ceramic heating body is composed of three parts of ceramic materials with different proportions, and the ceramic materials are as follows according to the weight proportion:

example one, a cigarette lighter, specification 90X5X4mm, 500 watts, 1100 ℃, 10 seconds processed to 1100 ℃.

1. Insulating ceramic material: silicon nitride Si₃N₄94%; ytterbium oxide Y₂O₃1-3%; aluminum oxide Al₂O₃0.5-1.5%; 0.2 to 0.5 percent of magnesium oxide MgO; lanthanum sesquioxide La₂O₃0.5-1%; hafnium oxide HfO₂0.2-0.5 percent of aluminum nitride AlN, 0.5-2 percent of aluminum nitride AlN, and the weight of all the components is 100 percent.

2. Heating ceramic material of silicon nitride Si₃N₄45%, solid solution of titanium carbide and titanium nitride, Ti (C, N), 26-35%; the weight ratio of titanium carbide to titanium nitride in solid solution is 4: 6; 0.5 to 3 percent of molybdenum powder Mo; 0.5 to 1.0 percent of nano nickel Ni; 0.2 percent of niobium carbide CHNb; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; SiO silicon oxide₂0.1-0.2%; aluminum oxide Al₂O₃5-10%, the weight of all components is 100%.

3. Welding a ceramic material: 60% of titanium carbide TiC; silicon nitride Si₃N₄20-30%; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; aluminum oxide Al₂O₃5-10%; SiO silicon oxide₂0.1-0.2%, the weight of all components is 100%.

The manufacturing method of the high-power silicon nitride ceramic heating chip with soft inside and hard outside comprises the following steps:

fourthly, hardening and degumming the whole body;

Example two, a dry sheet, 1200X12X4mm, 600 watts, 2 seconds processing to 258 ℃, durability 2 years. In the weight ratio of the three ceramic materials,

1. insulating ceramic material: silicon nitride Si₃N₄92%; ytterbium oxide Y₂O₃1-3%; aluminum oxide Al₂O₃0.5-1.5%; 0.2 to 0.5 percent of magnesium oxide MgO; lanthanum sesquioxide La₂O₃0.5-1%; hafnium oxide HfO₂0.2-0.5% of aluminum nitride AlN, 0.5-2%.

2. Heating ceramic material of silicon nitride Si₃N₄45%, solid solution of titanium carbide and titanium nitride, Ti (C, N), 26-35%; the weight ratio of titanium carbide to titanium nitride in solid solution is 4:6(ii) a 0.5 to 3 percent of molybdenum powder Mo; 0.5 to 1.0 percent of nano nickel Ni; 0.2 percent of niobium carbide CHNb; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; SiO silicon oxide₂0.1-0.2%; aluminum oxide Al₂O₃，5-10%。

3. Welding a ceramic material: titanium carbide TiC, 66%; silicon nitride Si₃N₄20-30%; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; aluminum oxide Al₂O₃5-10%; SiO silicon oxide₂，0.1-0.2%。

The remaining process conditions were the same as in example 1.

Example three, heat patch, specification 150X25X4mm, 800 watts, 10 seconds to 1000 ℃.

In the weight ratio of the three ceramic materials,

1. insulating ceramic material: silicon nitride Si₃N₄90 percent; ytterbium oxide Y₂O₃1-3%; aluminum oxide Al₂O₃0.5-1.5%; 0.2 to 0.5 percent of magnesium oxide MgO; lanthanum sesquioxide La₂O₃0.5-1%; hafnium oxide HfO₂0.2-0.5% of aluminum nitride AlN, 0.5-2%.

2. Heating ceramic material of silicon nitride Si₃N₄45%, solid solution of titanium carbide and titanium nitride, Ti (C, N), 26-35%; the weight ratio of titanium carbide to titanium nitride in solid solution is 4: 6; 0.5 to 3 percent of molybdenum powder Mo; 0.5 to 1.0 percent of nano nickel Ni; 0.2 percent of niobium carbide CHNb; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; SiO silicon oxide₂0.1-0.2%; aluminum oxide Al₂O₃，5-10%。

3. Welding a ceramic material: TiC, 72%; silicon nitride Si₃N₄20-30%; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; aluminum oxide Al₂O₃5-10%; SiO silicon oxide₂，0.1-0.2%。

The remaining process conditions were the same as in example 1.

Claims

1. The manufacturing method of the high-power silicon nitride ceramic heating sheet with the soft inside and the hard outside is characterized in that the ceramic heating sheet takes silicon nitride as a main raw material and comprises an insulating ceramic plate, heating ceramic, welding ceramic and an external lead, the heating ceramic arranged in a U shape is sintered on the central surface of the insulating ceramic plate, two ends of the heating ceramic are connected with the welding ceramic, one surface of the welding ceramic is exposed on the insulating ceramic plate and is a welding surface, and the external lead is welded on the welding surface;

the heating ceramic is formed by mixing conductive metal powder and non-conductive non-metal powder, the effect of adjusting resistance is achieved by adjusting the ratio of the metal powder to the non-metal powder, and the heating ceramic is electrified and heated to achieve the designed heating power;

the insulating ceramic plate is insulating composite ceramic with large heat capacity, and has high strength, thermal shock resistance and thermal stability;

welding ceramic, rapidly conducting electric energy to heating ceramic without heating, thereby protecting the low temperature of the wire outlet end and safely wiring;

the metal wire is welded on the exposed surface of the welding ceramic by an external lead, so that the outgoing line is firm and reliable;

the insulating ceramic material is characterized by comprising the following components in percentage by weight: silicon nitride Si₃N₄91.5-94%; ytterbium oxide Y₂O₃1-3%; aluminum oxide Al₂O₃0.5-1.5%; 0.2 to 0.5 percent of magnesium oxide MgO; lanthanum sesquioxide La₂O₃0.5-1%; hafnium oxide HfO₂0.2-0.5 percent of aluminum nitride (AlN), 0.5-2 percent of aluminum nitride (AlN), and the weight of all the components is 100 percent;

the heating ceramic material comprises silicon nitride Si₃N₄50%, solid solution of titanium carbide and titanium nitride, Ti (C, N), 35%; the weight ratio of titanium carbide to titanium nitride in solid solution is 4: 6; 3% of molybdenum powder Mo; 1.0 percent of nano nickel Ni; 0.2% of niobium carbide NbC; 0.5% of whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; SiO silicon oxide₂0.1-0.2%; aluminum oxide Al₂O₃10%, all components being 100% by weight;

the welding ceramic material comprises the following components in percentage by weight: 60-72% of titanium carbide TiC; nitrogen is present inSilicon oxide Si₃N₄20-30%; 0.2 to 0.5 percent of crystal whisker silicon carbide SiC; molybdenum silicide MoSi₂0.1-0.2%; aluminum oxide Al₂O₃5-10%; SiO silicon oxide₂0.1-0.2%, all components are 100% by weight;

the manufacturing method of the high-power silicon nitride ceramic heating piece with the soft inside and the hard outside comprises the following specific steps:

fourthly, hardening and degumming the whole body;

fifthly, putting the mixture into a hot isostatic pressing sintering furnace, sintering, reinforcing, hardening and forming, wherein the maximum sintering temperature is 1800-1820 ℃, and the pressure is as follows: 1500 Mpa; the composite processing and forming method is commonly called as: and (5) inner softening and outer hardening.