An environmentally friendly tin-antimony-rare earth composite semiconductor glaze and its lead-free low-temperature curing method

Abstract

The present invention discloses an environmentally friendly tin-antimony-rare earth composite semiconductor glaze and its lead-free low-temperature curing method, which is characterized by including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage ≥ 98%, and the rest being impurity phases; where n = 0.20 - 0.40, 4x + 3y = 4, 0.1 ≤ y ≤ 0.2, and A is a +3-valent rare earth element; the impurity phases are oxides of one or more elements among boron, silicon, bismuth, cobalt, strontium, calcium, and iron. This solution has a simple preparation process. The highest temperature during the entire preparation process is only about 1000°C, and the curing temperature is even 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.

Description

Technical Field

[0001] The present invention relates to the field of electroceramic glazes, and particularly to an environmentally friendly tin-antimony-rare earth composite semiconductor glaze and its lead-free low-temperature curing method. Background Art

[0002] The existence of semiconductor glazes is mainly to improve the electroceramics' ability to respond to the environment, and they need to have certain electrical and mechanical properties. Currently, semiconductor glazes often need to add lead elements, and the firing process temperature is too high, resulting in problems such as low cold and heat resistance and low bending strength.

[0003] Raw material selection is crucial. CN 116003162 B discloses an electroceramic 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-sized aluminum oxide, 3-5 parts of zirconia nanowires, and 2-3 parts of CaTi2O5 nanoparticles. The preparation process of this scheme is relatively complex, and it still has the characteristic of high sintering temperature. Tin oxide itself is a semiconductor oxide, but its reactivity in the glaze is very low and it is difficult to integrate into the glaze melt. Conventional techniques add antimony oxide to tin oxide to form a tin-antimony solid solution to improve the reactivity. During firing, part of the solid solution can integrate 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, but this will inevitably require a higher temperature. For example, CN 108218233 B discloses a semiconductor glaze for high-voltage ceramics and its preparation method, and the temperature reaches 1000-1200 °C. Summary of the Invention

[0004] To solve the above problems, the present invention proposes an environmentally friendly tin-antimony-rare earth composite semiconductor glaze and its lead-free low-temperature curing method, which has a simple preparation process. The highest temperature during the entire preparation process is only about 1000 °C, and the curing temperature is even 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:

[0006] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a chemical formula of Sn x A yThe main phase of O2·nSbO has a mass percentage ≥ 98%, and the rest are impurity phases; where n = 0.20 - 0.40, 4x + 3y = 4, 0.1 ≤ y ≤ 0.2, and A is a rare earth element with a valence of +3; the impurity phases are oxides of one or more elements among boron, silicon, bismuth, cobalt, strontium, calcium, and iron.

[0007] In this solution, a rare earth element with a valence of +3 is incorporated into the tin-antimony composite oxide, which can cause local electron mismatch, thereby introducing oxygen vacancies or defect energy levels, improving the carrier migration efficiency, and enhancing the electrical conductivity of the tin-antimony-rare earth composite semiconductor glaze; at the same time, the rare earth element can refine the grains and inhibit segregation during the high-temperature sintering process, making the thermal expansion coefficient of the glaze layer uniform, which is beneficial to improving weather resistance and wear resistance. This solution 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, enabling this solution to obtain the glaze at a relatively low sintering temperature condition.

[0008] Preferably, the rare earth element with a valence of +3 is lanthanum or yttrium.

[0009] The preparation method of the above-mentioned environmentally friendly tin-antimony-rare earth composite semiconductor glaze includes the following steps:

[0010] Step (1): According to the chemical formula ratio, dissolve rare earth oxide and tin oxide in hydrochloric acid, then adjust the pH to 8 - 10, filter to obtain a coprecipitate, wash the coprecipitate with ammonium carbonate water and dehydrate it, dry it and add boric acid or borate, and pre-burn it at 900 - 1000 °C, and crush it to obtain pre-burned material powder;

[0011] Step (2): According to the chemical formula ratio, mix the pre-burned material powder, antimony oxide powder and additive powder, dry grind for 15 - 30 min, sinter at 750 - 850 °C, and crush to obtain the environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0012] The purpose of step (1) in this solution is to prepare rare earth-doped tin oxide nanoparticles. This solution utilizes the reaction of rare earth oxide, tin oxide and hydrochloric acid to generate highly soluble chlorides, and then prepares tin hydroxide and rare earth hydroxide by the coprecipitation method. Since this solution selects chloride salts as the coprecipitation precursor, chloride ions will inevitably remain in the coprecipitate, and chloride ions will have a negative impact on the semiconductor glaze. This solution is essentially a composite material based on antimony tin oxide, and conductive crystal phases such as antimony tin oxide are easily combined with Cl -Reactions occur to form soluble salts, leading to problems such as glaze layer detachment, loose crystal phase structure, and conductive network. Additionally, it will also cause air holes, resulting in electric field concentration and triggering partial discharge, interfering with the signal transmission of semiconductor devices. Therefore, it is necessary to eliminate the influence of chloride ions as much as possible. In this solution, chloride ions are eliminated through the cleaning with ammonium bicarbonate solution and then dehydration, which can eliminate most of the residual chloride ions. Further, some of the residual chloride ions exist in the form of ammonium chloride with ammonium ions after drying. During the pre-burning process in step (1), ammonium chloride decomposes and volatilizes, further reducing the chloride ion content and making the chlorine content in the system at a very low level. On the other hand, the residual carbonate after cleaning can reduce the pre-burning reaction temperature. A lower pre-burning reaction temperature can refine the grains and form a glass phase with silicon dioxide, etc., making the pre-burning reaction of stannic hydroxide and rare earth hydroxide more sufficient. Then, 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: pre-burning and sintering. In the pre-burning in step (1), rare earth elements are doped into tin oxide, making the tin oxide obtain better activity and reducing the sintering temperature in step (2). During the sintering process in step (2), antimony trioxide has a low melting point and can coat the surface of tin oxide doped with rare earth elements to form composite particles. The antimony trioxide described in this solution is antimony trioxide.

[0013] Preferably, in step (1), the rare earth oxide is lanthanum oxide or yttrium oxide; the reagent for adjusting pH is sodium hydroxide or potassium hydroxide.

[0014] Preferably, in step (1), boric acid or borate accounting for 0.2 - 0.5% of the mass of the coprecipitate is added after drying, dry-ground for 15 - 30 min, and pre-burned at 900 - 1000 °C.

[0015] The addition of boric acid or borate can reduce the pre-burning temperature and promote the solid-phase reaction between rare earth ions and tin oxide. In this solution, the surface of the raw materials is activated by dry-grinding, enabling the raw material components to come into full contact, which is equivalent to densification, thereby improving the sufficiency of the pre-burning and sintering reactions.

[0016] Preferably, in step (1), pre-burn at 900 - 1000 °C for 30 - 60 min, and the heating rate during the pre-burning process is 2 - 5 °C / min.

[0017] 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.

[0018] Preferably, in step (2), according to the chemical formula ratio, the pre-burned material powder, antimony oxide powder, and additive powder are mixed, dry-ground for 15 - 30 min, and sintered at 750 - 850 °C.

[0019] Preferably, in step (2), it is sintered in rich oxygen at 750 - 850 °C for 30 - 60 min; the volume concentration of oxygen in the rich oxygen pre-sintering is 20 - 23%.

[0020] The heating and heat preservation in the sintering process control the reaction process, mainly to ensure sufficient reaction and prevent excessive grain size.

[0021] This solution optimizes the glaze network structure through additives, and then adjusts the electrical and mechanical properties.

[0022] This solution also proposes a lead-free low-temperature curing method for the above-mentioned environment-friendly tin-antimony-rare earth composite semiconductor glaze, including: green body sintering, green body surface treatment, glaze pulping and glazing, low-temperature curing; the concentration of the glaze after pulping is 40 - 50 Baumé degrees, 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 holding for 2 - 3 h.

[0023] Compared with the prior art, the technical advantages of this solution are:

[0024] 1. By coprecipitating tin oxide and rare earth element-containing substances and pre-sintering to obtain rare earth-doped tin oxide, and further sintering at high temperature with antimony oxide and then compounding to form antimony oxide-coated rare earth-doped tin oxide, it has environmental-friendly characteristics, does not require the addition of lead elements, and can reduce the curing temperature to 750 - 850 °C.

[0025] 2. This solution takes into account the influence of chloride ions when preparing the environment-friendly tin-antimony-rare earth composite semiconductor glaze. During the process of eliminating chloride ions, a small amount of carbonate is introduced by washing the coprecipitate with ammonium carbonate water and then dehydrating. The residual ammonium carbonate and ammonium chloride will decompose and volatilize during the pre-sintering process, and the residual sodium carbonate or potassium carbonate can promote grain homogenization, reduce the pre-sintering temperature, and reduce the porosity. Specific Embodiments

[0026] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a chemical formula of Sn x A yThe main phase of O2·nSbO, with a mass percentage of 98.5%, and the rest being miscellaneous phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the miscellaneous phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0029] It is prepared through the following steps:

[0030] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-burn for 40 min, and pulverize to obtain pre-burned powder;

[0031] Step (2): According to the chemical formula ratio, mix the pre-burned powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-burning is 22%, and pulverize to obtain an environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0032] Example 2

[0033] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.3%, and the rest being miscellaneous phases; where n = 0.40, y = 0.2, 4x + 3y = 4, and A is yttrium; the miscellaneous phases are oxides composed of boron, silicon, bismuth, cobalt, calcium, and iron, and the molar ratio of the corresponding elements is 3:2:1:1:1:1;

[0034] It is prepared through the following steps:

[0035] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 10 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, and under the condition of a heating rate of 5 °C / min, heat up to 1000 °C and pre-burn for 30 min, and pulverize to obtain pre-burned powder;

[0036] Step (2): According to the chemical formula ratio, mix the pre-sintered material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, calcium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 5 °C / min, heat up to 780 °C and perform oxygen-enriched sintering for 60 min. The volume concentration of oxygen in the oxygen-enriched pre-sintering is 21%. Crush to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0037] Example 3

[0038] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.8%, and the rest are impurity phases; where n = 0.25, y = 0.1, 4x + 3y = 4, and A is yttrium; the impurity phases are oxides of boron, silicon, strontium, calcium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1;

[0039] It is prepared through the following steps:

[0040] Step (1): According to the chemical formula ratio, dissolve yttrium oxide and tin oxide in hydrochloric acid, then adjust the pH to 8.5 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water, dehydrate, dry, add sodium borate accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, and under the condition of a heating rate of 2 °C / min, heat up to 900 °C and pre-sinter for 50 min. Crush to obtain the pre-sintered material powder;

[0041] Step (2): According to the chemical formula ratio, mix the pre-sintered material powder, antimony oxide powder with silica white powder, strontium oxide powder, calcium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 2 °C / min, heat up to 810 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-sintering is 21%. Crush to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0042] Example 4

[0043] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are impurity phases; where n = 0.30, y = 0.1, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1;

[0044] It is prepared through the following steps:

[0045] Step (1): According to the chemical formula ratio, dissolve rare earth oxide and tin oxide in hydrochloric acid, then adjust the pH to 9.5 with sodium hydroxide, filter to obtain a coprecipitate. Wash the coprecipitate with ammonium bicarbonate water with a mass fraction of 1%, dehydrate it, add boric acid accounting for 0.3% of the mass of the coprecipitate after drying, grind it dry for 25 min, and under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-calcine for 60 min, and pulverize to obtain a pre-calcined material powder;

[0046] Step (2): According to the chemical formula ratio, mix the pre-calcined material powder, antimony oxide powder, silica white powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 780 °C and perform oxygen-enriched sintering for 50 min. The volume concentration of oxygen in the oxygen-enriched pre-calcination is 22%, and pulverize to obtain an environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that rare earth elements are not added, specifically:

[0049] An environment-friendly tin-antimony composite semiconductor glaze, including a main phase with the chemical formula SnO2·nSbO, accounting for 98.5% by mass percentage, and the rest are miscellaneous phases; where n = 0.30; the miscellaneous phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0050] It is prepared through the following steps:

[0051] According to the chemical formula ratio, mix tin oxide, boric acid accounting for 0.3% of the mass of tin oxide, antimony oxide powder, silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-calcination is 22%, and pulverize to obtain an environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that the purity of the main phase is too low and the n value is too large, specifically:

[0054] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, accounting for 97.5% by mass percentage, and the rest are miscellaneous phases; where n = 0.60, y = 0.15, 4x + 3y = 4, A is lanthanum; the miscellaneous phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0055] Prepared by the following steps:

[0056] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium bicarbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-burn for 40 min, and pulverize to obtain a pre-burned material powder;

[0057] Step (2): According to the chemical formula ratio, mix the pre-burned material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-burning is 22%, and pulverize to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0058] Comparative Example 3

[0059] It is different from Example 1 in that the coprecipitate is not washed with ammonium bicarbonate water, specifically:

[0060] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are impurity phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0061] Prepared by the following steps:

[0062] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash with deionized water and dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-burn for 40 min, and pulverize to obtain a pre-burned material powder;

[0063] Step (2): According to the chemical formula ratio, mix the pre-burned material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-burning is 22%, and pulverize to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0064] Comparative Example 4

[0065] It is different from Example 1 in that the pre-sintering temperature in step (1) is too high, specifically:

[0066] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are miscellaneous phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the miscellaneous phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0067] It is prepared through the following steps:

[0068] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium bicarbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 1150 °C for pre-sintering for 40 min, and crush to obtain pre-sintered material powder;

[0069] Step (2): According to the chemical formula ratio, mix the pre-sintered material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 800 °C for oxygen-enriched sintering for 40 min. The volume concentration of oxygen in the oxygen-enriched pre-sintering is 22%, and crush to obtain the environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0070] Comparative Example 5

[0071] It is different from Example 1 in that the pre-sintering temperature in step (1) is too low, specifically:

[0072] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are miscellaneous phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the miscellaneous phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0073] It is prepared through the following steps:

[0074] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate. Wash the coprecipitate with 1% ammonium bicarbonate water by mass, dehydrate it, dry it, add boric acid accounting for 0.3% of the mass of the coprecipitate, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat it to 850 °C and pre-burn for 40 min, then crush it to obtain pre-burned powder;

[0075] Step (2): According to the chemical formula ratio, mix the pre-burned powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat it to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen for oxygen-enriched pre-burning is 22%, and then crush it to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0076] Comparative Example 6

[0077] It is different from Example 1 in that the value of y is too large, specifically:

[0078] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are impurity phases; where n = 0.30, y = 0.25, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0079] It is prepared through the following steps:

[0080] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate. Wash the coprecipitate with 1% ammonium bicarbonate water by mass, dehydrate it, dry it, add boric acid accounting for 0.3% of the mass of the coprecipitate, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat it to 950 °C and pre-burn for 40 min, then crush it to obtain pre-burned powder;

[0081] Step (2): According to the chemical formula ratio, mix the pre-burned powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, grind it dry for 30 min, and under the condition of a heating rate of 3 °C / min, heat it to 800 °C and perform oxygen-enriched sintering for 40 min. The volume concentration of oxygen for oxygen-enriched pre-burning is 22%, and then crush it to obtain an environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0082] Comparative Example 7

[0083] It is different from Example 1 in that the value of y is too small, specifically:

[0084] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest being impurity phases; where n = 0.30, y = 0.05, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0085] It is prepared through the following steps:

[0086] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-burn for 40 min, and crush to obtain pre-burned powder;

[0087] Step (2): According to the chemical formula ratio, mix the pre-burned powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 800 °C and perform oxygen-rich sintering for 40 min. The volume concentration of oxygen in the oxygen-rich pre-burning is 22%, and crush to obtain the environmentally friendly tin-antimony-rare earth composite semiconductor glaze.

[0088] Comparative Example 8

[0089] The difference from Example 1 is that it is not sintered under oxygen-rich conditions. Specifically:

[0090] An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest being impurity phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0091] It is prepared through the following steps:

[0092] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-burn for 40 min, and crush to obtain pre-burned powder;

[0093] Step (2): According to the chemical formula ratio, mix the pre-sintered material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 800 °C and sinter for 40 min. The volume concentration of oxygen in the pre-sintering is 18%, and then crush to obtain an environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0094] Comparative Example 9

[0095] The difference from Example 1 is that the sintering temperature is too high, specifically:

[0096] An environment-friendly tin-antimony-rare earth composite semiconductor glaze, including a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage of 98.5%, and the rest are impurity phases; where n = 0.30, y = 0.15, 4x + 3y = 4, and A is lanthanum; the impurity phases are oxides of boron, silicon, bismuth, cobalt, strontium, and iron, and the molar ratio of the corresponding elements is 3:1:1:1:1:1;

[0097] It is prepared through the following steps:

[0098] Step (1): According to the chemical formula ratio, dissolve lanthanum oxide and tin oxide in hydrochloric acid, then adjust the pH to 9 with sodium hydroxide, filter to obtain a coprecipitate, wash the coprecipitate with 1% ammonium carbonate water by mass, dehydrate, dry, add boric acid accounting for 0.3% of the mass of the coprecipitate, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 950 °C and pre-sinter for 40 min, and then crush to obtain the pre-sintered material powder;

[0099] Step (2): According to the chemical formula ratio, mix the pre-sintered material powder, antimony oxide powder with silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, and iron oxide powder, dry grind for 30 min, and under the condition of a heating rate of 3 °C / min, heat up to 900 °C and sinter in an oxygen-rich environment for 40 min. The volume concentration of oxygen in the oxygen-rich pre-sintering is 22%, and then crush to obtain an environment-friendly tin-antimony-rare earth composite semiconductor glaze.

[0100] Performance detection:

[0101] According to the lead-free low-temperature curing method of the environment-friendly tin-antimony-rare earth composite semiconductor glaze proposed in this solution, prepare the glaze surface. The preparation process includes: green body sintering, surface treatment of the green body, glaze slurrying and glazing, and low-temperature curing; the concentration of the glaze after slurrying is 45 Baumé, and the thickness of the glaze layer is 0.8 mm; the low-temperature curing process is: heat up to 800 °C at a rate of 1.5 °C / min and keep warm for 2.5 h; the glazing method is dip glazing.

[0102] The items to be detected are as follows:

[0103] 1. Determine the volume resistivity according to GB / T5594.5-1995 "Test Method for Volume Resistivity of Structural Ceramic Materials for Electronic Components - Test Method for Volume Resistivity";

[0104] 2. Determine the flexural strength according to GB / T6569-2006 "Test Method for Flexural Strength of Fine Ceramics";

[0105] 3. Thermal shock resistance: Put the glazed product into an oven at 300°C, keep it warm for 20 minutes, take it out and quench it in water at 4°C, and record the highest number of repeated times without cracks;

[0106] 4. Abrasion resistance: Evaluate with reference to GBT3810.7-2016 Test Methods for Ceramic Tiles.

[0107] The results of performance detection are shown in Table 1.

[0108] Table 1

[0109]

[0110] From the result analysis of Examples 1-4 and Comparative Examples 1-9, Examples 1-4 of this solution can obtain specimens with good comprehensive performance. Taking Example 1 as a comparison below, analyze the possible reasons for the low performance of Comparative Examples 1-9.

[0111] In Comparative Example 1, no rare earth element was added and it was directly prepared with oxides, which could not adapt to the low-temperature curing process and had poor overall performance; in Comparative Example 7, the rare earth doping amount was too small, resulting in low performance; in Comparative Example 6, the doping amount was excessive, which would lead to too low resistance and a decrease in mechanical properties. Thus, it can be seen that there is an optimal range for the rare earth doping amount, and both excessive and too little amounts will lead to low performance.

[0112] In Comparative Example 2, the purity of the main phase was too low, resulting in an increase in the proportion of intergranular heterophases, leading to lower electrical properties than those in Example 1. In addition, due to the difference in the thermal expansion coefficients of the heterophases, it was easy to crack, so the thermal shock resistance was poor.

[0113] In Comparative Example 3, the coprecipitate was not washed with ammonium carbonate solution, and there might be a certain amount of residual chloride ions. In addition, a small amount of residual ammonium ions and carbonate ions in Example 1 could capture free tin ions and lanthanum ions and change the pre-burning 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 superimposed effect of insufficient doping amount and the influence of chloride ions.

[0114] In Comparative Example 4, the pre-sintering temperature was too high, resulting in over-sized grains and a decline in overall performance. The same situation occurred in Comparative Example 9 with too high a sintering temperature; in contrast, in Comparative Example 5, due to too low a pre-sintering temperature, the solid-phase reaction between rare earth elements and tin oxide was insufficient, and the effect of changing the crystal structure of tin oxide was not achieved, so it showed poor electrical and wear resistance.

[0115] In Comparative Example 8, sintering was not carried out under oxygen-rich conditions, resulting in too many oxygen vacancies in the system, too many lattice mismatch points, which were likely to become crack sources, causing poor resistance to heat and cold and a decline in flexural strength.

Claims

1. An environmentally friendly tin-antimony-rare earth composite semiconductor glaze, characterized in that, Comprising a main phase with the chemical formula Sn x A y O2·nSbO, with a mass percentage ≥ 98%, and the rest being impurity phases; where n = 0.20 - 0.40, 4x + 3y = 4, 0.1 ≤ y ≤ 0.2, and A is a rare earth element with a valence of +3; the impurity phases are oxides of one or more elements among boron, silicon, bismuth, cobalt, strontium, calcium, and iron; The environment-friendly tin-antimony-rare earth composite semiconductor glaze is prepared through the following steps: Step (1): According to the chemical formula ratio, dissolve rare earth oxide and tin oxide in hydrochloric acid, then adjust the pH to 8-10, filter to obtain a coprecipitate, wash the coprecipitate with ammonium bicarbonate water and dehydrate it, add boric acid or borate after drying, pre-burn at 900-1000 °C, and pulverize to obtain pre-burned powder; Step (2): According to the chemical formula ratio, mix the pre-burned powder, antimony oxide powder and additive powder, dry grind for 15-30 min, sinter at 750-850 °C, and pulverize to obtain the environment-friendly tin-antimony-rare earth composite semiconductor glaze.

2. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, wherein The +3 valence rare earth element is lanthanum or yttrium.

3. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, wherein In step (1), the rare earth oxide is lanthanum oxide or yttrium oxide; the reagent for adjusting the 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), add boric acid or borate accounting for 0.2-0.5% of the mass of the coprecipitate after drying, dry grind for 15-30 min, and pre-burn 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-burn at 900-1000 °C for 30-60 min, and the heating rate during the pre-burning 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 silica white powder, bismuth oxide powder, cobalt oxide powder, strontium oxide powder, calcium oxide powder, iron oxide powder.

7. The environmentally friendly tin-antimony-rare earth composite semiconductor glaze according to claim 1, wherein In step (2), under the condition of 750-850 °C, perform oxygen-enriched sintering for 30-60 min; the volume concentration of oxygen in the oxygen-enriched sintering is 21-23%.

8. A lead-free low-temperature curing method for the environment-friendly tin-antimony-rare earth composite semiconductor glaze according to any one of claims 1-7, comprising: Firing of the green body, surface treatment of the body, pulping and glazing of the glaze, and low-temperature curing; The concentration of the glaze after pulping is 40-50 Baumé degrees, 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 holding for 2-3 h.

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