Heating substrate for thermal print head resistant to high energy impact and manufacturing method thereof

Abstract

The present invention relates to the technical field of thermal print head manufacturing, and more specifically, to a high-energy impact-resistant heating substrate for a thermal print head capable of improving the product's energy impact resistance, and a manufacturing method thereof. The substrate comprises an insulating substrate and is characterized in that an electrode conductor comprises an electrode conductor segment resistant to high-energy impact, wherein the electrode conductor segment resistant to high-energy impact is provided with a lower electrode wire and an upper electrode wire, wherein the lower electrode wire is made of a hafnium-rhenium (HfRe) alloy, has a thickness ranging from 0.1 to 2.0 μm, and has a hafnium (Hf) content of less than 10% of the total mass percentage, and the upper electrode wire is made of a hafnium-iridium alloy, is located on the surface of the lower electrode wire, has a thickness ranging from 0.05 to 0.2 μm, and has a hafnium (Hf) content of less than 10% of the total mass percentage.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal print head manufacturing, in particular to a high-energy impact-resistant heating substrate for a thermal print head capable of improving the energy impact resistance of the product and a manufacturing method thereof. Background Art

[0002] The thermal print head is a component that prints using Joule heat. During printing, the temperature of the printing area is very high, and in special circumstances it can reach over 1000°C. Existing thermal print heads have difficulty meeting this temperature requirement.

[0003] Patent document CN102815971 discloses an Hf(Ta)C ultrahigh-temperature multiphase coating. The coating is composed of HfC and HfTaC2, with a mole fraction of HfTaC2 ranging from 6% to 50% and distributed uniformly or in a gradient throughout the coating. The preparation method involves placing a surface-treated substrate in a low-pressure chemical vapor deposition (LPCVD) furnace. A mixed powder of hafnium tetrachloride and tantalum pentachloride is used as the hafnium and tantalum sources; methane is used as the carbon source; argon is used as the diluent; and hydrogen is used as the reducing gas. The mixed powder is then transported into the deposition furnace reactor, where it is deposited on the substrate surface to form the Hf(Ta)C ultrahigh-temperature multiphase coating.

[0004] Patent document CN109320303 provides an ultra-high temperature oxidation-resistant and ablation-resistant coating and a preparation method thereof, relating to the field of chemical vapor deposition technology. The present invention provides an ultra-high temperature oxidation-resistant and ablation-resistant coating, comprising a Ta / (Ta,Hf)C multi-layer multiphase composite coating formed by alternating superposition of a metal Ta coating and a (Ta,Hf)C multiphase coating. A method for preparing an ultra-high temperature oxidation-resistant and ablation-resistant coating is also provided, the steps of which are as follows: S01, providing a pretreated substrate material; S02, preparing a (Ta,Hf)C multiphase coating on the surface of the substrate material, and preparing a metal Ta transition coating on the surface of the (Ta,Hf)C multiphase coating, alternating deposition multiple times, and finally ending the deposition with a (Ta,Hf)C multiphase coating to prepare a Ta / (Ta,Hf)C multi-layer multiphase composite coating. It is suitable for preparing ultra-high temperature protective coatings on the inner pore surfaces of substrates such as graphite and C / C composite materials, and improving the oxidation resistance, ablation resistance, and thermal shock resistance of the inner pore working surface of the substrate material.

[0005] Patent document CN109972120 relates to a method for preparing a multi-component composite carbide coating. It comprises the following steps: (1) placing a mixed powder of TaCl5, HfCl4, and ZrCl4 into a crucible under an inert atmosphere; (2) placing a substrate sample on a support in a deposition furnace, introducing argon gas, and heating to the deposition temperature; (3) placing the crucible containing the mixed powder on a lifting support in the low-temperature zone of a dual-temperature zone gasification furnace, connecting the crucible mouth to the high-temperature zone, setting the heating temperatures of the low and high-temperature zones, and heating to completely vaporize the mixed powder; (4) introducing H2 and CH4 into the deposition furnace, and then introducing the completely vaporized mixed gas into the deposition furnace using a carrier gas, and performing deposition under normal pressure. This preparation method can obtain a multi-component composite coating with an accurate stoichiometric ratio of each component, and can ensure that the coating is tightly and firmly bonded to the substrate material and has excellent stability.

[0006] Patent document CN111072388B, which relates to a long-term ablation-resistant ultra-high melting point nitrogen-containing carbide ultra-high temperature ceramic and its application, provides a method for preparing HfC with a density greater than or equal to 98% and a uniform C / N content distribution by ball milling + spark plasma sintering. x N y Ceramics. The new ultra-high melting point ceramics designed and prepared overcome the defects of existing ultra-high temperature ablation-resistant ceramics, such as too low ablation temperature or too rapid ablation loss at high temperatures, making them suitable for ultra-high temperature ablation protection at 3000°C and above.

[0007] The above literatures all involve Hf(Ta)C or HfC x N y Research on high temperature resistant coatings. However, the electrode wire components and heating resistor components of thermal print heads must meet the requirements of heat resistance and conductivity at the same time. Existing hafnium carbon nitride and related materials cannot be directly used in the manufacture of thermal print heads. Summary of the Invention

[0008] In view of the shortcomings and deficiencies in the prior art, the present invention proposes a high-energy impact-resistant heating substrate for a thermal print head and a manufacturing method thereof, which can improve the energy impact resistance of the product.

[0009] The present invention is achieved by the following measures:

[0010] A heating substrate for a thermal print head resistant to high-energy impacts comprises an insulating substrate, an underglaze layer provided on the insulating substrate, a heating resistor and electrode wires arranged on the underglaze layer, and a protective layer covering the heating resistor and part of the electrode wires. The electrode wires comprise an electrode wire segment resistant to high-energy impacts, wherein the electrode wire segment resistant to high-energy impacts comprises a lower electrode wire and an upper electrode wire, the lower electrode wire being made of a hafnium-rhenium (HfRe) alloy, having a thickness in the range of 0.1-2.0 μm, and a hafnium (Hf) content in the lower electrode wire being less than 10% of the total mass percentage, and the upper electrode wire being made of a hafnium-iridium alloy, being located on the surface of the lower electrode wire, and having a thickness in the range of 0.05-0.2 μm, and a hafnium (Hf) content in the lower electrode wire being less than 10% of the total mass percentage.

[0011] The electrode wire of the present invention also includes an ordinary wire segment connected to the high-energy impact-resistant electrode wire segment. The ordinary wire segment is made of aluminum wire. The high-energy impact-resistant electrode wire segment is only distributed in an area 0.3 mm away from the heating resistor.

[0012] The heating resistor of the present invention adopts HfC x N y Made of a mixture of HfC and SiC x N y The ratio is between 30% and 70%, the thickness of the heating resistor is 10 to 500 nm, and the resistivity of the heating resistor is 500 to 4000E-8Ω.m.

[0013] The base glaze layer of the present invention includes a base glaze heat storage layer with SiO2 as the main material and an HfO2 layer located on the upper surface of the base glaze heat storage layer. The thickness of the base glaze heat storage layer is between several um and several hundred um; the thermal conductivity of the base glaze heat storage layer is 1±0.5W / mK, and the thermal expansion coefficient is 6.5±1e-6 / ℃; an HfO2 layer with a thickness of 0.1~10um is provided on the surface of the base glaze heat storage layer. The melting point of HfO2 is 2758℃, which can improve the power resistance and temperature resistance of the print head; the thermal conductivity of the HfO2 layer is 1.6~2W / mK, and the thermal conductivity similar to that of the base glaze heat storage layer can maintain similar thermal response characteristics. The thermal expansion coefficient of HfO2 is 6±1e-6 / ℃. The similar thermal expansion coefficient can avoid interlayer peeling due to thermal expansion and contraction.

[0014] The insulating protective film in the protective layer of the present invention is composed of at least one of a HfO2 & SiN mixture, a HfO2 & SiON mixture, or a HfO2 & SiAlON mixture, the proportion of HfO2 is less than 20%, the total thickness is between 1 and 20 μm, SiN is an electrical insulating material, the temperature resistance is about 1900 ° C, and the thermal expansion coefficient is 2.35 ± 0.5e-6 / ° C; SiAlON is an electrical insulating material, the melting point is greater than 1500 ° C, the heat shock resistance is greater than 900 ° C, and the thermal expansion coefficient is 2.6 ± 0.5e-6 / ° C. Both are excellent temperature-resistant materials, and the expansion coefficient is the same as the HfO2 layer in the bottom glaze layer and the HfC in the heating resistor. x N y The similar thermal expansion coefficients of the materials can avoid interlayer delamination due to thermal expansion and contraction.

[0015] The present invention also proposes a method for manufacturing a heating substrate for a thermal print head as described above, characterized in that the heating element layer resistant to high energy impact is made by PVD or CVD process, and the heating resistor layer is made of HfC x N y and SiC mixture, and then adopts photolithography process, uses photoresist as protective layer, and dry etching forms resistance layer pattern, and the etching gas is selected from Ar, CF4, CHF3, O2, etc.; the electrode wire segment resistant to high energy impact can be made by two methods. The first method is to first form an electrode wire layer by PVD or CVD process, and then adopt photolithography process, use photoresist to cover the unnecessary pattern by wet etching, and form a wire pattern; the second method is to first cover the surface of the resistor pattern with photoresist, and then perform photolithography and development, and then form an electrode wire layer by PVD or CVD process, and finally remove the photoresist and the electrode wire layer above to form an electrode wire pattern. Here, since the resistor layer is generally very thin, it is not easy to be placed on top of the electrode to avoid disconnection due to the step difference.

[0016] In the method for manufacturing a heating substrate for a thermal print head according to the present invention, the heating resistor is manufactured by the following method:

[0017] Step 1: Prepare HfC powder, HfN powder, and SiC powder in a mass ratio of HfC:HfN:SiC = (1-3):(1-3):(1-2). The specific ratio is adjusted according to the resistance value of the print head to be made. The purity of HfC, HfN, and SiC is greater than or equal to 99.9%. The prepared HfC powder, HfN powder, and SiC powder are ball-milled to refine the particles and mix them evenly. The mixed powder is filtered to obtain a powder with a particle size of less than 5 μm.

[0018] Step 2: Plasma sintering the obtained mixed powder. The plasma sintering conditions are as follows: the temperature in the sintering furnace is 2100-2500°C, the temperature is kept for 15-20 minutes, the pressure is 35-50 MPa, and the vacuum degree is less than 2 Pa.

[0019] Step 3: The sintered material is cut into required sizes and welded to the target base to make a PVD target;

[0020] Step 4: Use PVD magnetron sputtering process to prepare the heating resistor layer by DC or RF method, put the substrate with the base glaze into the cavity, and set the vacuum degree in the cavity to 1×10 -4 Pa, the heating chamber temperature is 150~300℃, argon is introduced, and the pressure is 0.1~5Pa.

[0021] In step 4 of the present invention, since the material is conductive, direct current (DC) is preferred, as the sputtering efficiency is higher. The film layer is prepared using magnetron sputtering technology. In order to improve the density and adhesion of the material, a direct current pulse mode can be further adopted on the basis of the DC mode. The conditions are a frequency of 50-150kHz and a pulse power density of 4-7W / cm 2 , the duty cycle is 20~45%, and the air pressure is 0.2~0.8Pa.

[0022] The base glaze layer and the electrode layer of the present invention can both be prepared by directly sputtering the corresponding target materials; the electrode can be prepared by DC or RF magnetron sputtering process if it is a conductive material; the base glaze heat storage layer can be prepared by RF magnetron sputtering process if it is a non-conductive material; the protective layer can be prepared by single-target sputtering, the single target is prepared by mixed plasma sintering method, or two independent dual targets are used. When sputtering two independent target materials, the method of sputtering in the same cavity can be adopted according to different proportions. Because the target material is non-conductive, the protective layer is prepared by RF magnetron sputtering process.

[0023] Compared with the prior art, the present invention significantly improves the heat resistance of the product by providing an electrode wire segment that is resistant to high-energy impact, and further correspondingly provides a heating resistor, a base glaze layer and a protective layer that are resistant to high-energy impact. It can also meet the conductivity requirements of the corresponding devices. From the heat storage layer to the heating element, to the electrode, and then to the protective layer, the Hf element runs through the entire process, which can maintain the fusion between the layers and the thermal expansion coefficients between the related components are similar, thereby effectively overcoming the problem of interlayer peeling caused by thermal expansion and contraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attachment Figure 1 It is a cross-sectional view of a heating substrate for a thermal print head according to the present invention.

[0025] Attachment Figure 2 It is a schematic diagram of the local structure of the electrode wire in the present invention.

[0026] Attachment Figure 3 This is a partial cross-sectional view of the heating resistor region of the heating substrate for the thermal print head of the present invention.

[0027] Reference numerals: insulating substrate 1 , underglaze layer 2 , underglaze heat storage layer 2 - 1 , HfO 2 layer 2 - 2 , heating resistor 3 , electrode layer 4 , lower electrode line 4 - 1 , upper electrode line 4 - 2 , common electrode 4 a , individual electrode 4 b , protective layer 5 . DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example

[0029] This example provides a heating substrate for a high-energy-resistant thermal print head, comprising an insulating substrate 1, an underglaze layer 2, a heating resistor 3, individual electrodes 4b, a common electrode 4a, and a protective layer 5. The protective layer 5 includes an insulating protective layer, and a wear-resistant protective layer can be added on the insulating protective layer as needed.

[0030] In this example, the bottom glaze layer 2 adopts a composite structure of a bottom glaze heat storage layer 2-1 with SiO2 as the main material and a HfO2 layer 2-2; the heating resistor 3 adopts HfC x N y and SiC mixed composition, including at least two kinds of conductive materials and insulating materials, so as to adjust the resistivity of the heating resistor through proportion; part of the electrode wires (electrode wire segments resistant to high-energy impact) adopts a double-layer structure, the lower electrode wire is composed of Hf+Re alloy, and the upper electrode wire is composed of Hf+Ir alloy; the insulating protective layer in the protective layer is composed of at least one of a HfO2&SiN mixture, a HfO2&SiON mixture, or a HfO2&SiAlON mixture.

[0031] In this example, the base glaze heat storage layer 2-1 is made of a mixture of ordinary base glaze materials, such as compounds composed of elements such as Si, O, B, Zr, Ca, and Al, and is prepared by a printing and sintering thick film process with a thickness ranging from a few um to several hundred um; the thermal conductivity of the base glaze heat storage layer is about 1W / mK, and the thermal expansion coefficient is 6.5±1e-6 / ℃; the HfO2 layer 2-2 is made on the surface of the base glaze heat storage layer by PVD, CVD and other processes, with a thickness of 0.1~10um. The melting point of HfO2 is 2758℃, which can improve the power resistance and temperature resistance of the print head; the thermal conductivity of the HfO2 layer 2-2 is 1.6~2W / mK, and the thermal conductivity similar to that of the lower layer can maintain similar thermal response characteristics. The thermal expansion coefficient of HfO2 is 6±1e-6 / ℃. The similar thermal expansion coefficient can avoid interlayer delamination due to thermal expansion and contraction.

[0032] The heating resistor 3 provided in this example has good bonding strength with the base glaze layer and the protective layer. The heating resistor layer selected is made of HfC x N y Composition of mixture with SiC, HfC x N y The ratio is between 30% and 70%, the thickness is 10~500nm, the resistivity of the mixture is 500~4000E-8Ω.m, and the selected heating resistor layer is made by PVD or CVD process. x N y The melting point can reach above 4000℃, which is much higher than the melting point of Ta, which is 2996℃ and oxidation temperature is about 500℃, which is commonly used in heating elements. It has been verified that after ultra-long (300s) ablation, HfC x N y Ceramics still maintain a near-zero ablation rate and a continuous and stable anti-oxidation protection structure; HfC x N y The thermal expansion coefficient is 6.73±1 e-6 / ℃, and the thermal expansion coefficient of SiC is 4±1e-6 / ℃. The two are relatively close, and are also relatively close to the HfO2 layer below. The thermal expansion coefficients of traditional heating element materials Ta and SiO2 are 15.8±1 e-6 / ℃ and 6.5±1 e-6 / ℃ respectively, which are quite different, and are also quite different from the HfO2 layer below. x N y The resistivity is 36.33±2e-8Ω·m, and SiC is insulated. The two can obtain different square resistances by adjusting different proportions to meet different resistance requirements. It is also similar to traditional heating element materials Ta (resistivity is 15e-8Ω·m) and SiO2 (insulation), and can form a substitute.

[0033] In this example, the resistance pattern of the heating resistor body, the sputtered resistance layer HfC x N y A mixture of SiC and SiC is made using a photolithography process, with photoresist as a protective layer and dry etching to form the resistor layer pattern. Commonly used etching gases include Ar, CF4, CHF3, O2, etc.

[0034] In this example, the electrode layer 4 of some electrode conductors adopts a double-layer structure. The lower electrode line 4-1 is composed of Hf+Re alloy, the Hf ratio is less than 10%, and the thickness is 0.1~2um; the upper electrode 4-2 is composed of Hf+Ir alloy, the Hf ratio is less than 10%, and the thickness is 0.05~0.2um. The selected electrode layer 4 is made by PVD or CVD processes. The melting points of Hf+Re are 2227℃ and 3180℃, respectively, which are much higher than the melting point of Al, which is about 600℃ commonly used now. The thermal expansion coefficient of Hf+Re is 5.8±1 e-6 / ℃ and 6.7±1 e-6 / ℃, which is less than 23 e-6 / ℃ of Al, and is similar to the expansion coefficient of the heating element in the lower layer. In addition, the Re metal has good plasticity and toughness to ensure that it will not break at high temperatures; the resistivity of Hf+Re is 35.7 e-8Ω·m The Hf+Ir alloy has a conductivity of 5.42e-8Ω·m, which is greater than Al's 2.83e-8Ω·m. Therefore, it is limited to use near heating elements with high temperature requirements, and the Hf ratio cannot be too high. In order to obtain better oxidation resistance, a thin Hf+Ir alloy conductive layer with a thickness of 0.05~0.2um is made outside the Hf+Re alloy. Ir has excellent oxidation resistance and can withstand oxidation up to 2100℃. The thermal expansion coefficient of Ir is 6.4±1e-6 / ℃, which is similar to that of the lower electrode 1. The resistivity is 4.7e-8Ω·m, which is also similar to the lower electrode line.

[0035] The electrode layer in this example can be realized by a variety of process methods, for example: sputtering the electrode layer Hf+Re alloy and Hf+Ir alloy, using a photolithography process, photoresist as a protective layer, wet etching to form the electrode layer pattern, and various acid liquids as wet chemicals; Method 2, using a photolithography process, photoresist to protect unnecessary images, sputtering the electrode layer Hf+Re alloy and Hf+Ir alloy, removing the photoresist and the electrode layer above, leaving the pattern outside the photoresist to form the electrode layer pattern.

[0036] In this example, the insulating protective film is made of at least one of a HfO2 & SiN mixture, a HfO2 & SiON mixture, or a HfO2 & SiAlON mixture, with the proportion of HfO2 being less than 20% and the total thickness being between 1 and 20 μm. SiN is electrically insulating, with a temperature resistance of approximately 1900°C and a thermal expansion coefficient of 2.35±0.5e-6 / °C; SiAlON is electrically insulating, with a melting point greater than 1500°C, a heat shock resistance greater than 900°C, and a thermal expansion coefficient of 2.6±0.5e-6 / °C. Both are relatively excellent temperature-resistant materials, and their expansion coefficients are the same as those of the HfO2 of the lower glaze 2 and the HfC of the heating element. x N yThe insulating protective film can be made by the Lift-Off process, in which bentonite powder is prepared into a special slurry, the electrode pattern to be exposed is covered by a printing process, and an insulating protective film HfO2&SiN mixture or HfO2&SiON mixture or HfO2&SiAlON mixture is sputtered. Finally, the bentonite and the insulating protective film above are removed to form an insulating protective film pattern.

[0037] In this example, Hf elements are used throughout the entire process from the heat storage layer to the heating element, to the electrode, and then to the protective layer, which can maintain the fusion between the layers.

[0038] The heating resistor in this example can be made by the following method:

[0039] S1: Prepare HfC powder, HfN powder, and SiC powder in a mass ratio of HfC:HfN:SiC = 2:3:2. The specific ratio is adjusted according to the resistance value of the print head to be made. The purity of HfC, HfN, and SiC is greater than or equal to 99.9%. The prepared HfC powder, HfN powder, and SiC powder are refined by ball milling and mixed uniformly. The mixed powder is filtered to obtain a powder with a particle size of less than 5 μm.

[0040] S2: The resulting mixed powder is plasma sintered. The conditions for plasma sintering are: a furnace temperature of 2100-2500°C (the melting points of HfC, HfN, and SiC are 3928°C, 3305°C, and 2827°C, respectively). The plasma sintering temperature does not necessarily need to reach the melting point of the materials being sintered. Spark plasma sintering (SPS) allows for rapid densification of powder particles at temperatures below their melting point. The process is maintained for 15-20 minutes at a pressure of 35-50 MPa and a vacuum of less than 2 Pa.

[0041] S3: The sintered material is cut into required sizes and welded to the target base to make a PVD target;

[0042] S4: Using PVD magnetron sputtering process, the specific steps are as follows: Direct current (DC) or radio frequency (RF) can be used. Since the material is conductive, DC is preferred, as it has higher sputtering efficiency. Place the substrate with the base glaze into the chamber and set the vacuum degree in the chamber to 1×10 -4 Pa, the heating chamber temperature is 150~300℃, argon is introduced, the pressure is 0.1~5Pa, and the film layer is prepared using magnetron sputtering technology. In order to improve the density and adhesion of the material, a DC pulse method can be further used on the basis of the DC mode. The conditions are a frequency of 50~150k and a pulse power density of 4-7w / cm 2 , the duty cycle is 20~45%, the air pressure is 0.2~0.8Pa, and the generated film is dense and has excellent performance.

[0043] The HfO2 layer in the base glaze and the high-energy impact-resistant electrode conductor segments (Hf+Re alloy, Hf+Ir alloy) are prepared using the same methods as for heating elements, directly sputtering the corresponding target materials. Conductive electrodes can be produced using DC or RF magnetron sputtering. Since the HfO2 layer is a non-conductive material, it is produced using RF magnetron sputtering. The protective film (HfO2&SiN or HfO2&SiON or HfO2&SiAlON) is prepared using the same methods as for heating elements. The target can be a single target produced using hybrid plasma sintering, or two independent targets can be used. In these cases, sputtering can be performed simultaneously in the same chamber at varying ratios. Because the target is non-conductive, the protective film is produced using RF magnetron sputtering.

Claims

1. A heating substrate for a thermal print head resistant to high energy impact, comprising an insulating substrate, an underglaze layer on the insulating substrate, a heating resistor and electrode wires arranged on the underglaze layer, and a protective layer covering the heating resistor and part of the electrode wires, characterized in that: The electrode wire includes an electrode wire segment resistant to high-energy impact, wherein the electrode wire segment resistant to high-energy impact is provided with a lower electrode wire and an upper electrode wire, wherein the lower electrode wire is made of a hafnium-rhenium (HfRe) alloy, the thickness of the lower electrode wire is in the range of 0.1-2.0 μm, and the hafnium (Hf) content in the lower electrode wire is less than 10% of the total mass percentage, and the upper electrode wire is made of a hafnium-iridium alloy, the upper electrode wire is located on the surface of the lower electrode wire, and the thickness is in the range of 0.05-0.2 μm, and the hafnium (Hf) content in the lower electrode wire is less than 10% of the total mass percentage.

2. The high-energy impact-resistant heating substrate for a thermal print head according to claim 1, wherein: The electrode wire also includes a common wire segment connected to the high-energy impact-resistant electrode wire segment. The common wire segment is made of aluminum wire. The high-energy impact-resistant electrode wire segment is only distributed in an area 0.3 mm away from the heating resistor.

3. The high-energy impact-resistant heating substrate for a thermal print head according to claim 1, wherein: The heating resistor is HfC x N y Made of a mixture of HfC and SiC x N y The ratio is between 30% and 70%, the thickness of the heating resistor is 10 to 500 nm, and the resistivity of the heating resistor is 500 to 4000 e-8 Ω·m.

4. The high-energy impact-resistant heating substrate for a thermal print head according to claim 1, wherein: The bottom glaze layer includes a bottom glaze heat storage layer with SiO2 as the main material and a HfO2 layer located on the upper surface of the bottom glaze heat storage layer; the thermal conductivity of the bottom glaze heat storage layer is 1±0.5W / mK, and the thermal expansion coefficient is 6.5±1e-6 / ℃; an HfO2 layer with a thickness of 0.1~10um is provided on the surface of the bottom glaze heat storage layer, the thermal conductivity of the HfO2 layer is 1.6~2W / mK, and the thermal expansion coefficient of HfO2 is 6±1e-6 / ℃.

5. The high-energy impact-resistant heating substrate for a thermal print head according to claim 1, wherein: The insulating protective film in the protective layer is composed of at least one of a mixture of HfO2 and SiN, a mixture of HfO2 and SiON, or a mixture of HfO2 and SiAlON, the proportion of HfO2 is less than 20%, the total thickness is between 1 and 20 μm, SiN is electrically insulating, has a temperature resistance of 1900°C, and a thermal expansion coefficient of 2.35±0.5e-6 / °C, SiAlON is electrically insulating, has a melting point greater than 1500°C, is resistant to thermal shock greater than 900°C, and has a thermal expansion coefficient of 2.6±0.5e-6 / °C.

6. A method for manufacturing a heating substrate for a thermal print head according to any one of claims 1 to 5, characterized in that: In the method for manufacturing the heating substrate for the thermal print head, the heating resistor is manufactured by the following method: Step 1: Prepare HfC powder, HfN powder, and SiC powder in a mass ratio of HfC:HfN:SiC = (1-3):(1-3):(1-2). The specific ratio is adjusted according to the resistance value of the print head to be made. The purity of HfC, HfN, and SiC is greater than or equal to 99.9%. The prepared HfC powder, HfN powder, and SiC powder are ball-milled to refine the particles and mix them evenly. The mixed powder is filtered to obtain a powder with a particle size of less than 5 μm. Step 2: Plasma sintering the obtained mixed powder. The plasma sintering conditions are as follows: the temperature in the sintering furnace is 2100-2500°C, the temperature is kept for 15-20 minutes, the pressure is 35-50 MPa, and the vacuum degree is less than 2 Pa. Step 3: The sintered material is cut into required sizes and welded to the target base to make a PVD target; Step 4: Use PVD magnetron sputtering process to prepare the heating resistor layer by DC or RF method, put the substrate with the base glaze into the cavity, and set the vacuum degree in the cavity to 1×10 -4 Pa, the heating chamber temperature is 150~300℃, argon is introduced, and the pressure is 0.1~5Pa.

7. The method for manufacturing a heat generating substrate for a thermal print head according to claim 6, wherein: In step 4, due to the conductivity of the material, DC is selected and DC pulse is used with a frequency of 50-150kHz and a pulse power density of 4-7w / cm 2 , the duty cycle is 20~45%, and the air pressure is 0.2~0.8Pa.

8. The method for manufacturing a heat generating substrate for a thermal print head according to claim 6, wherein: The heating element resistance layer resistant to high energy impact adopts a photolithography process, uses photoresist as a protective layer, and forms a resistance layer pattern by dry etching, and the etching gas is selected from Ar, CF4, CHF3, and O2.

Images