Environment-friendly tin antimony-rare earth composite semiconductor glaze and lead-free low-temperature curing method thereof

Abstract

The environment-friendly tin antimony-rare earth composite semiconductor glaze is characterized in that the environment-friendly tin antimony-rare earth composite semiconductor glaze comprises a main phase with the chemical formula of SnxAyO2. NSbO, the mass percentage of the main phase is larger than or equal to 98%, and the balance is an impure phase; wherein n is equal to 0.20-0.40, 4x + 3y is equal to 4, y is greater than or equal to 0.1 and less than or equal to 0.2, and A is a + 3 valence rare earth element; the impure phase is an oxide of one or more of boron, silicon, bismuth, cobalt, strontium, calcium and iron. According to the scheme, the preparation process is simple, the highest temperature in the whole preparation process is only about 1000 DEG C, the curing temperature is only about 800 DEG C, and the prepared environment-friendly tin antimony-rare earth composite semiconductor glaze has good electrical properties, cold and heat resistance and bending strength.

Description

Technical Field

[0001] The invention relates to the field of electric porcelain glazes, and in particular to an environmentally friendly tin-antimony-rare earth composite semiconductor glaze and a lead-free low-temperature curing method thereof. Background Art

[0002] The existence of semiconductor glaze is mainly to improve the ability of electrical porcelain to cope with the environment, and it needs to have certain electrical and mechanical properties. Current semiconductor glazes often need to add lead elements, and the firing process temperature is too high, resulting in low cold and heat resistance and low bending strength.

[0003] The selection of raw materials is very critical. CN 116003162 B discloses an electric porcelain semiconductor glaze, which is made by mixing the following raw materials in parts by weight: 30-35 parts of potassium feldspar, 25-30 parts of kaolin, 20-25 parts of quartz powder, 8-10 parts of calcined talc, 8-10 parts of ball clay, 5-7 parts of barium titanate, 3-5 parts of indium tin oxide, 3-5 parts of strontium tantalum oxynitride, 3-5 parts of nano zinc oxide, 3-5 parts of micron-grade aluminum oxide, 3-5 parts of zirconium oxide nanowires, and 2-3 parts of CaTi2O5 nanoparticles. The preparation process of this solution is relatively complicated, and the sintering temperature is still high. Tin oxide itself is a semiconductor oxide, but its reactivity in glaze is very low and it is difficult to be integrated into the glaze melt. Conventional technology adds antimony oxide to tin oxide to form a tin-antimony solid solution to improve the reactivity. During firing, part of the solid solution can be integrated into the glass melt, so that the thin, originally insulating matrix glass between the cassiterite grains also has the ability to allow carriers to pass through, that is, it is easier to form a carrier channel. However, this inevitably requires a higher temperature. For example, CN 108218233 B discloses a semiconductor glaze for high-pressure ceramics and a preparation method thereof, with a temperature of 1000-1200°C. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes an environmentally friendly tin-antimony-rare earth composite semiconductor glaze and a lead-free low-temperature curing method thereof, which has a simple preparation process, the highest temperature of the entire preparation process is only about 1000°C, and the curing temperature is only about 800°C. The prepared environmentally friendly tin-antimony-rare earth composite semiconductor glaze has good electrical properties, cold and heat resistance and bending strength.

[0005] To achieve the above object, the technical solution of the present invention is: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A yThe main phase of O2·nSbO has a mass percentage of ≥98%, and the rest is an impurity phase; wherein n=0.20-0.40, 4x+3y=4, 0.1≤y≤0.2, and A is a +3-valent rare earth element; the impurity phase is an oxide of one or more elements selected from boron, silicon, bismuth, cobalt, strontium, calcium, and iron.

[0006] This scheme incorporates +3-valent rare earth elements into tin-antimony composite oxides, which can cause local electron mismatch, thereby introducing oxygen vacancies or defect energy levels, improving carrier migration efficiency, and improving the conductivity of tin-antimony-rare earth composite semiconductor glazes; at the same time, rare earth elements can refine grains, inhibit segregation during high-temperature sintering, and make the thermal expansion coefficient of the glaze layer consistent, which is beneficial to improving weather resistance and wear resistance. This scheme does not add lead elements, there is no lead element dissolution, and it is environmentally friendly. By regulating the addition of impurity elements, the sintering temperature can be adjusted, so that this scheme can obtain glazes at lower sintering temperatures.

[0007] Preferably, the +3-valent rare earth element is lanthanum or yttrium.

[0008] The method for preparing the above-mentioned environmentally friendly tin-antimony-rare earth composite semiconductor glaze comprises the following steps: Step (1): dissolving rare earth oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 8-10, filtering to obtain a coprecipitate, washing the coprecipitate with ammonium carbonate water, dehydrating, drying, adding boric acid or borate, pre-calcining at 900-1000°C, and crushing to obtain a pre-calcined material powder; Step (2): Mix the pre-fired powder, antimony oxide powder and additive powder according to the chemical formula, dry grind for 15-30 minutes, sinter at 750-850° C., and grind to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0009] The purpose of step (1) of this scheme is to prepare a rare earth-doped tin oxide nanoparticle. This scheme utilizes the reaction of rare earth oxide, tin oxide and hydrochloric acid to generate highly soluble chloride salt, and then prepares tin hydroxide and rare earth hydroxide by coprecipitation. Since this scheme uses chloride salt as a coprecipitation precursor, chloride ions will inevitably remain in the coprecipitate, and chloride ions will have a negative impact on semiconductor glazes. This scheme is essentially a composite material based on antimony tin oxide. Conductive crystals such as antimony tin oxide are easily reacted with Cl -The reaction generates soluble salts, which lead to problems such as glaze detachment, loose crystal structure, and conductive network. In addition, it also causes pores, resulting in electric field concentration and local discharge, which interferes with the signal transmission of semiconductor devices. Therefore, the influence of chloride ions must be eliminated as much as possible. This solution eliminates chloride ions by washing with ammonium carbonate solution and then dehydrating, which can eliminate most of the residual chloride ions. Furthermore, some of the residual chloride ions and ammonium ions exist in the form of ammonium chloride after drying. During the pre-firing process of step (1), ammonium chloride decomposes and volatilizes, further reducing the content of chloride ions, so that the chlorine content in the system is at an extremely low state. On the other hand, the carbonate remaining after washing can reduce the pre-firing reaction temperature. A lower pre-firing reaction temperature can refine the grains and form a glass phase with silicon dioxide, etc., so that the pre-firing reaction of tin hydroxide and rare earth hydroxide is more sufficient. After the sintering in step (2) is completed, the overall expansion coefficient can be made uniform and the porosity can be reduced. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze is prepared in two steps, namely, pre-firing and sintering. In the pre-firing of step (1), rare earth elements are doped into tin oxide, so that the tin oxide has better activity and the sintering temperature of step (2) is reduced. In the sintering process of step (2), antimony oxide has a low melting point and can be coated on the surface of tin oxide doped with rare earth elements to form composite particles. The antimony oxide described in this scheme is antimony trioxide.

[0010] Preferably, in step (1), the rare earth oxide is lanthanum oxide or yttrium oxide; and the reagent for adjusting pH is sodium hydroxide or potassium hydroxide.

[0011] Preferably, in step (1), after drying, 0.2-0.5% of the mass of the coprecipitate is added with boric acid or borate, dry-milled for 15-30 minutes, and pre-calcined at 900-1000°C.

[0012] The addition of boric acid or borate can reduce the pre-sintering temperature and promote the solid phase reaction of rare earth ions and tin oxide. This solution activates the surface of the raw materials through dry grinding, so that the raw material components are fully contacted, which is equivalent to densification, thereby improving the adequacy of the pre-sintering and sintering reactions.

[0013] Preferably, in step (1), pre-sintering is performed at 900-1000°C for 30-60 min, and the heating rate during the pre-sintering process is 2-5°C / min.

[0014] Preferably, in step (2), the additive powder is one or more of white carbon black powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, calcium oxide powder, and iron oxide powder.

[0015] Preferably, in step (2), the pre-sintered material powder, antimony oxide powder and additive powder are mixed according to the chemical formula ratio, dry-milled for 15-30 minutes, and sintered at 750-850°C.

[0016] Preferably, in step (2), oxygen-enriched sintering is performed at 750-850° C. for 30-60 min; the oxygen volume concentration of the oxygen-enriched pre-sintering is 20-23%.

[0017] The heating and insulation of the sintering process controls the progress of the reaction, mainly to ensure sufficient reaction and prevent the grains from being too large.

[0018] This scheme optimizes the glaze network structure through additives, thereby adjusting the electrical and mechanical properties.

[0019] This scheme also proposes a lead-free low-temperature curing method for the above-mentioned environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including: biscuit sintering, body surface treatment, glaze slurrying and glazing, and low-temperature curing; the concentration of the glaze after slurrying is 40-50 degrees Baume, and the thickness of the glaze layer is 0.5-1.5mm; the low-temperature curing process is: heating to 750-850℃ at 1-2℃ / min and keeping warm for 2-3h.

[0020] Compared with the existing technology, the technical advantages of this solution are: 1. Rare earth-doped tin oxide is prepared by co-precipitating tin oxide and rare earth element-containing substances and pre-firing, and then further sintered with antimony oxide at high temperature to form antimony oxide-coated rare earth-doped tin oxide, which has environmentally friendly properties, does not require the addition of lead elements, and can reduce the curing temperature to 750-850°C.

[0021] 2. This scheme takes into account the influence of chloride ions when preparing environmentally friendly tin-antimony-rare earth composite semiconductor glazes. In the process of eliminating chloride ions, a small amount of carbonate is introduced by dehydrating the co-precipitate after washing with ammonium carbonate water. The residual ammonium carbonate and ammonium chloride will decompose and volatilize during the pre-firing process. The residual sodium carbonate or potassium carbonate can promote grain homogenization, reduce the pre-firing temperature, and reduce porosity. DETAILED DESCRIPTION

[0022] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1 An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A yThe main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0024] Example 2 An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.3% by mass, and the rest is impurity phase; n=0.40, y=0.2, 4x+3y=4, A is yttrium; the impurity phase is an oxide of boron, silicon, bismuth, cobalt, calcium, and iron, and the molar ratio of each element is 3:2:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 10 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 1000°C at a heating rate of 5°C / min, pre-calcining for 30 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired material powder, antimony oxide powder, white carbon black powder, bismuth oxide powder, cobalt oxide powder, calcium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 780°C at a heating rate of 5°C / min, and sintered in oxygen-enriched conditions for 60 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired material is 21%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0025] Example 3 An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.8% by mass, and the rest is impurity phase; n=0.25, y=0.1, 4x+3y=4, A is yttrium; impurity phase is oxides of boron, silicon, strontium, calcium, and iron, and the molar ratio of each element is 3:1:1:1:1; Prepared by the following steps: Step (1): dissolving yttrium oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 8.5 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of sodium borate to the coprecipitate, dry grinding for 30 minutes, heating to 900°C at a heating rate of 2°C / min, pre-calcining for 50 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, strontium oxide powder, calcium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 810°C at a heating rate of 2°C / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 21%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0026] Example 4 An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.1, 4x+3y=4, A is lanthanum; impurity phase is oxides of boron, silicon, cobalt, strontium, and iron, and the molar ratio of each element is 3:1:1:1:1; Prepared by the following steps: Step (1): dissolving rare earth oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9.5 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 25 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 60 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 780°C at a heating rate of 3°C / min, and sintered in oxygen-enriched conditions for 50 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0027] Comparative Example 1 The difference from Example 1 is that no rare earth element is added, specifically: An environmentally friendly tin-antimony composite semiconductor glaze comprises a main phase with a chemical formula of SnO2·nSbO, with a mass percentage of 98.5%, and the rest is a miscellaneous phase; wherein n=0.30; the miscellaneous phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1:1; Prepared by the following steps: Tin oxide, boric acid (0.3% by mass of tin oxide), antimony oxide powder, white carbon black powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula, dry-ground for 30 minutes, heated to 800°C at a heating rate of 3°C / min, and sintered in oxygen-enriched conditions for 40 minutes. The oxygen volume concentration of the oxygen-enriched pre-firing is 22%, and the environmentally friendly tin-antimony-rare earth composite semiconductor glaze is obtained by pulverizing.

[0028] Comparative Example 2 The difference from Example 1 is that the main phase purity is too low and the n value is too large, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 97.5% by mass, and the rest is impurity phase; n=0.60, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0029] Comparative Example 3 The difference from Example 1 is that the coprecipitate is not washed with ammonium carbonate water, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing with deionized water and dehydrating, drying, adding 0.3% boric acid by weight of the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0030] Comparative Example 4 The difference from Example 1 is that the pre-burning temperature in step (1) is too high, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 1150°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0031] Comparative Example 5 The difference from Example 1 is that the pre-burning temperature in step (1) is too low, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 850°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0032] Comparative Example 6 The difference from Example 1 is that the y value is too large, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.25, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0033] Comparative Example 7 The difference from Example 1 is that the y value is too small, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.05, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0034] Comparative Example 8 The difference from Example 1 is that the sintering is not carried out under oxygen-rich conditions, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A yThe main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 800°C at a heating rate of 3°C / min, and sintered for 40 minutes. The pre-fired oxygen volume concentration is 18%, and crushed to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0035] Comparative Example 9 The difference from Example 1 is that the sintering temperature is too high, specifically: An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, comprising a chemical formula of Sn x A y The main phase of O2·nSbO is 98.5% by mass, and the rest is impurity phase; n=0.30, y=0.15, 4x+3y=4, A is lanthanum; the impurity phase is oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1; Prepared by the following steps: Step (1): dissolving lanthanum oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 9 with sodium hydroxide, filtering to obtain a coprecipitate, washing the coprecipitate with 1% by mass ammonium carbonate water, dehydrating, drying, adding 0.3% by mass of boric acid to the coprecipitate, dry grinding for 30 minutes, heating to 950°C at a heating rate of 3°C / min, pre-calcining for 40 minutes, and crushing to obtain a pre-calcined powder; Step (2): pre-fired powder, antimony oxide powder, white carbon powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder and iron oxide powder are mixed according to the chemical formula ratio, dry-milled for 30 minutes, heated to 900° C. at a heating rate of 3° C. / min, and sintered in oxygen-enriched conditions for 40 minutes, wherein the oxygen volume concentration of the oxygen-enriched pre-fired powder is 22%, and ground to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0036] Performance testing: According to the lead-free low-temperature curing method of the environmentally friendly tin-antimony-rare earth composite semiconductor glaze proposed in this scheme, a glaze is prepared, and the preparation process includes: sintering of the blank, surface treatment of the blank, glaze slurrying and glazing, and low-temperature curing; the concentration of the glaze after slurrying is 45 degrees Baume, and the thickness of the glaze layer is 0.8 mm; the low-temperature curing process is: heating to 800°C at 1.5°C / min and keeping warm for 2.5 hours; the glazing method is immersion glazing.

[0037] The test contents include: 1. Determine the volume resistivity according to GB / T5594.5-1995 "Test Methods for Performance of Structural Ceramic Materials for Electronic Components and Devices - Test Methods for Volume Resistivity"; 2. Determine the flexural strength according to GB / T6569-2006 "Test method for flexural strength of fine ceramics"; 3. Cold and heat resistance: Put the glazed product into a 300℃ oven, keep it warm for 20 minutes, take it out and quench it in 4℃ water, and record the highest number of repetitions without cracks; 4. Wear resistance: Refer to GBT3810.7-2016 ceramic tile test method for evaluation.

[0038] The performance test results are shown in Table 1.

[0039] Table 1

[0040] From the analysis of the results of Examples 1-4 and Comparative Examples 1-9, Examples 1-4 of the present scheme can obtain samples with good comprehensive performance. The following is a comparison with Example 1 to analyze the possible reasons for the poor performance of Comparative Examples 1-9.

[0041] Comparative Example 1 does not add rare earth elements and is directly prepared with oxides, which cannot adapt to the low-temperature curing process and has poor overall performance; Comparative Example 7 has too little rare earth doping, resulting in low performance; Comparative Example 6 is a case of excessive doping, which will lead to too low resistance and reduced mechanical properties. It can be seen that there is an optimal range for rare earth doping, and excessive or too little rare earth doping will lead to low performance.

[0042] The main phase purity of Comparative Example 2 is too low, resulting in an increase in the proportion of intergranular impurity phases, resulting in lower electrical properties than Example 1. In addition, due to the difference in thermal expansion coefficients of the impurity phases, it is easy to crack, so the cold and heat resistance is poor.

[0043] In Comparative Example 3, the co-precipitate was not washed with ammonium carbonate solution, and there may be certain residual chloride ions. In addition, the small amount of residual ammonium ions and carbonate ions in Example 1 can capture free tin ions and lanthanum ions, and change the pre-firing atmosphere, making it easier for rare earth elements to enter the tin oxide lattice. Therefore, the poor performance of Comparative Example 3 may essentially be a superposition effect of insufficient doping and the influence of chloride ions.

[0044] In Comparative Example 4, the pre-firing temperature is too high, resulting in overly large grains and a decrease in overall performance. The same situation is also found in Comparative Example 9 where the sintering temperature is too high. On the contrary, in Comparative Example 5, the pre-firing temperature is too low, resulting in insufficient solid-phase reaction between the rare earth elements and tin oxide, which fails to change the crystal structure of tin oxide, and thus performs poorly in terms of electrical properties and wear resistance.

[0045] Comparative Example 8 was not sintered under oxygen-rich conditions, resulting in too many oxygen vacancies in the system, which made the lattice mismatch points too many, and easily became crack sources, causing the cold and heat resistance to deteriorate, and the bending strength to decrease.

Claims

1. An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, characterized in that: Including chemical formula Sn x A y The main phase of O2·nSbO has a mass percentage of ≥98%, and the rest is an impurity phase; wherein n=0.20-0.40, 4x+3y=4, 0.1≤y≤0.2, and A is a +3-valent rare earth element; the impurity phase is an oxide of one or more elements selected from boron, silicon, bismuth, cobalt, strontium, calcium, and iron; The environmentally friendly tin-antimony-rare earth composite semiconductor glaze is prepared by the following steps: Step (1): dissolving rare earth oxide and tin oxide in hydrochloric acid according to the chemical formula ratio, then adjusting the pH to 8-10, filtering to obtain a coprecipitate, washing the coprecipitate with ammonium carbonate water, dehydrating, drying, adding boric acid or borate, pre-calcining at 900-1000°C, and crushing to obtain a pre-calcined material powder; Step (2): Mix the pre-fired powder, antimony oxide powder and additive powder according to the chemical formula, dry grind for 15-30 minutes, sinter at 750-850° C., and grind to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

2. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, characterized in that: The +3 valent rare earth element is lanthanum or yttrium.

3. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, characterized in that: In step (1), the rare earth oxide is lanthanum oxide or yttrium oxide; and the reagent for adjusting pH is sodium hydroxide or potassium hydroxide.

4. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, characterized in that: In step (1), after drying, 0.2-0.5% of the mass of the coprecipitate is added with boric acid or borate, dry-milled for 15-30 minutes, and pre-calcined at 900-1000°C.

5. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 4, characterized in that: In step (1), pre-sintering is performed at 900-1000°C for 30-60 min, and the heating rate during the pre-sintering process is 2-5°C / min.

6. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, characterized in that: In step (2), the additive powder is one or more of white carbon black powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, calcium oxide powder, and iron oxide powder.

7. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, characterized in that: In step (2), the pre-sintered powder, antimony oxide powder and additive powder are mixed according to the chemical formula ratio, dry-milled for 15-30 minutes, and sintered at 750-850°C.

8. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 7, characterized in that: In step (2), oxygen-enriched sintering is performed at 750-850° C. for 30-60 min; the oxygen volume concentration of the oxygen-enriched pre-sintering is 20-23%.

9. A lead-free low-temperature curing method for the environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to any one of claims 1 to 8, comprising: Green body sintering, green body surface treatment, glaze slurrying and glazing, low temperature curing; The concentration of the glaze after slurrying is 40-50 degrees Baume, and the thickness of the glaze layer is 0.5-1.5 mm; the low-temperature curing process is: heating to 750-850° C. at 1-2° C. / min and keeping warm for 2-3 hours.

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