A Q-salt intermediate, a preparation method, a method for preparing Q-salt and P-salt, and their applications

Abstract

The present invention discloses a Q-salt intermediate, a preparation method, a method for preparing Q-salt and P-salt, and their applications; the Q-salt intermediate is a mononuclear diammine platinum intermediate [Pt(NH3)2](HPO4), in which only 2 ammonia molecules are coordinated to the four hybrid orbitals of platinum in the intermediate, and the remaining 2 are empty orbitals, and the external charge is balanced by hydrogen phosphate. When using this intermediate to prepare P-salt and Q-salt, the yields are both >99%; in addition, the bath solution prepared with this intermediate shows good thermal stability, long-term stability, throwing power and dispersion ability; when electroplating on K414 alloy and IC21 alloy, after the deposited platinum layer obtained is subjected to Al infiltration and high-temperature oxidation, the surface of the test piece is complete, without oxide scale and local corrosion points generated, belonging to the completely antioxidant level and having excellent ultra-high temperature antioxidant performance.

Description

Technical Field

[0001] The present invention relates to a Q salt intermediate, a preparation method, a method for preparing Q salt and P salt, and their applications. Specifically, the Qs-2R electroplating platinum source dissociates into freely moving anions and cations after being energized from the binuclear platinum complex [{Pt(NH3)2}(HPO4)]2, and the mononuclear platinum complex [Pt(NH3)2](HPO4) crystallizes out after work. In addition, the application of the bath solution configured with the Qs-2R platinum source on the superalloy has a good application prospect for the deposited platinum layer on the superalloy. Background Art

[0002] Electroplating platinum is a common technical means in surface treatment. The stability of the coordination between platinum element and ligand directly affects the current density and determines the performance of the deposited layer.

[0003] Pt 2+ has an outer nuclear electron structure of dsp 2 hybridization, generally forming a four-coordinate planar structure. The divalent platinum with two coordination is unstable and difficult to separate and purify. The commonly used divalent platinum source in electroplating is: Pt(NH3)2(NO2)2 (P salt),

[0004] [Pt(NH3)4](HPO4) (Q salt) and K2[Pt(H2O)2(NO2)2](SO4) (DNS salt). Among them, except the first one is tetravalent platinum, the rest are divalent platinum with a four-coordinate structure, as follows:

[0005]

[0006] The structures of these platinum complexes are well-known, and there are also many synthesis processes for them. Most of the synthesis methods use silver salts to remove chlorine elements. Trevor.G et al. reported a silver salt-free synthesis method, using K2Pt(NO2)4 and acid as raw materials to first obtain the +3-valent binuclear platinum complex [{(H2O)Pt(μ-SO4)2}2] 2- and [{(H2O)Pt(μ-HPO4)2}2] 2- . This complex is oxidized to tetravalent binuclear platinum under the combined action of O2 and HNO3 to obtain a series of complexes similar to "DNS salt". Compared with the traditional silver salt chlorine removal process, this method greatly reduces the production cost.

[0007] The cathode efficiency of the CPA (chloroplatinate) process is extremely high, the deposition stress is low, and a large amount of chlorine is easy to corrode the metal substrate; the +2-valent "P salt" or "Q salt" process itself does not contain sulfur and chlorine, can effectively improve the quality of the coating, significantly reduce the residual sulfur and chlorine on the substrate, and show good distribution characteristics and precise thickness control, but during use, it is necessary to periodically add ammonia and nitrite to adjust the pH value to maintain a high cathode current efficiency. Ammonia is a harmful gas, and exhaust ventilation is always essential; at the same time, the diamine-coordinated "P salt" is easy to change from diamine to triamine and then to tetraamine in an ammonia-containing system, and tetraamine is a stable complex cation. Under such process conditions, there is a tendency to reduce the overall efficiency of the cathode of the plating solution; the DNS process is a strong acidic electroplating tank. The electroplating solution not only corrodes the metal substrate layer, but the residual sulfur and chlorine are mixed in the deposited platinum layer. Under high temperature conditions, it is easy to generate gas to form holes, and the inner wall of the hole is oxidized at high temperature, causing the coating to fall off and fail.

[0008] In addition, the stability of the platinum complex structure has a great influence on the performance of the plating solution. With high structural stability, the cathode efficiency is high, the obtained coating is dense, the substrate and the deposited platinum layer are not easy to diffuse each other during high-temperature diffusion, and alloying is difficult; on the contrary, with low complex stability, the deposition rate is high, the density is low after alloying, and the high-temperature oxidation resistance is weak. Therefore, the selection of a platinum source with moderate stability has a great influence on the performance of the deposited platinum layer. Summary of the invention

[0009] To this end, the present invention aims to control the deposition rate and efficiency of platinum atoms on the substrate and enhance the high-temperature oxidation corrosion resistance of the high-temperature alloy. A +2-valent platinum complex ion with moderate stability under power-on is designed and synthesized, and the bath solution is configured with the platinum source. The high-temperature oxidation resistance of the deposited platinum layer on the single crystal high-temperature alloy is investigated under the proprietary bath solution formula and process.

[0010] The technical solution of the present invention is:

[0011] The structure of a "Q salt" intermediate [Pt(NH3)2](HPO4) is:

[0012]

[0013] In this structure, only two of the four hybrid orbitals of platinum are coordinated by ammonia, and the remaining two orbitals are empty. The external charge is balanced by hydrogen phosphate. This structure is an excellent intermediate for the synthesis of "P salt" and "Q salt".

[0014] The mononuclear diamine platinum intermediate and the method for preparing "P salt" and "Q salt" using the intermediate include:

[0015] Step 1, Synthesis of binuclear platinum complex [{Pt(NH3)2}(HPO4)]2:

[0016] This reaction is carried out under the protection of an inert gas. Since gas is generated during the process, it is necessary to timely extract it from the reaction system.

[0017] Weigh a certain amount of chloroplatinic acid salt, dissolve it in distilled water, then add nitrite, and boil until the solution color turns to hay color; after cooling, add a dilute phosphoric acid solution, react with stirring at 80 °C for 3 h, and the solution color turns to hay color again. Concentrate the mother liquor to obtain a bright red precipitate, wash it with distilled water until there are no impurity ions, and keep the red precipitate in a moist state for standby;

[0018] Step 2, synthesis of mononuclear diammineplatinum intermediate [Pt(NH3)2](HPO4):

[0019] Take the moist red insoluble substance from Step 1, add a certain amount of dilute ammonium dihydrogen phosphate solution acidified, react until the red solid completely dissolves into a hay-colored solution, rotary evaporate to remove a large amount of solvent, take the filter cake after filtration, wash it with a small amount of ice water to obtain a white crystalline solid, and vacuum dry it at a certain temperature to obtain the target intermediate;

[0020] Furthermore, synthesize "Q salt" from this intermediate:

[0021] Take a certain amount of the "Q salt" intermediate from Step 2, add a certain amount of ammonia water, stir for 1 h at a certain temperature, heat to remove the excess ammonia, adjust the pH to neutral, and dilute with water to a platinum content of 2% - 4% to obtain an aqueous solution of "Q salt";

[0022] Furthermore, synthesize "P salt" from this intermediate:

[0023] Weigh a certain amount of the "Q salt" intermediate from Step 2, add a certain amount of nitrite, stir for 1 h at a certain temperature, cool to room temperature, filter, wash the filter cake with distilled water, and vacuum dry the filter cake at a certain temperature to obtain a white or light yellowish green "P salt" solid.

[0024]

[0025] Furthermore, the binuclear platinum [{Pt(NH3)2}(HPO4)]2 in which the oxygen of the polybasic oxyacid directly coordinates with platinum, and the polybasic oxyacid can also be sulfate radical and carboxylate radical, and the reaction formula is as follows:

[0026]

[0027] Furthermore, in the preparation method of the binuclear platinum complex, the molar ratio of the materials is [PtCl6] 2- : NO2 - : dilute acid = 1:6 - 10:1.

[0028] Further, the material chloroplatinic acid salt includes any one of H2PtCl6·6H2O, K2PtCl6, and Na2PtCl6.

[0029] Further, the reaction in the preparation method of the binuclear platinum complex is carried out in an inert atmosphere, and the gas discharged at the beginning of the reaction needs to be discharged from the system in time.

[0030] Further, in the preparation method of the mononuclear diamminoplatinum intermediate, the molar ratio of the materials is platinum: ammonium dihydrogen phosphate = 1:1 - 4.

[0031] Further, in the preparation method of synthesizing "Q salt" with [Pt(NH3)2](HPO4), the molar ratio of the materials is platinum: ammonia water = 1:4 - 10.

[0032] Further, in the preparation method of synthesizing "P salt" with [Pt(NH3)2](HPO4), the molar ratio of the materials is platinum: nitrite = 1:2 - 10.

[0033] Further, the material nitrite includes: NaNO2 and KNO2.

[0034] An application of a "Q salt" intermediate in preparing an electroplating solution as a platinum source.

[0035] Further, the aqueous solution after dissociation of the electroplating solution prepared with the platinum source is neutral, and the anion after dissociation can also be used as a buffer system to control the working environment of the bath: [H2PO4] - ~[HPO4] 2- ~[PO4] 3- , and it has a wide applicable pH range.

[0036] Further, for the electroplating solution prepared with the "Q salt" intermediate as the platinum source, appropriate additives can be added according to different deposition requirements to obtain different types of electroplating bath solutions. Adding a small amount of NH3 gives a "Q salt" bath electroplating solution, and adding NO2 - gives a "P salt" bath electroplating solution.

[0037] Further, an application of the electroplating solution prepared with the "Q salt" intermediate as the platinum source in electroplating a platinum layer on superalloys K414 and IC21.

[0038] Further, the K 2+ of the "Q salt" intermediate [Pt(NH3)2] 稳 is smaller than that of the "P salt" or "Q salt", and the degree of alloying after thermal diffusion of the deposited layer is higher. 稳

[0039] The beneficial effects of the present invention:

[0040] (1) The bath solution prepared with the "Q salt" intermediate as the platinum source has the following characteristics:

[0041] The aqueous solution has high thermal stability and will not decompose or produce insoluble substances even when heated to boiling.

[0042] After 18 months of continuous operation, the bath solution will gradually turn light yellow, but no black precipitate will be produced. Moreover, the bath solution has high transparency, good heat resistance and stability, and the risks associated with large-scale continuous electroplating production are relatively low.

[0043] (2) The deposited layer obtained after the above bath solution works has the following characteristics:

[0044] The deposited platinum layer on the K414 alloy is uniformly silver-white in appearance, without common electroplating defects such as peeling, blistering, ablation, and abnormal color; the surface of the coating is flat, with high density, no obvious cracks or inclusions, and the cross-section of the coating is uniform without through longitudinal cracks.

[0045] (3) When depositing a 15.85-μm platinum layer on the IC21 alloy, the bonding layer has a high density and a low vacuum high-temperature diffusion rate, and can form an oxide film on the surface. The platinum coating can improve the adhesion between the oxide film and the substrate. After the 1150°C, 100-h assessment, the oxide film on the surface of the plated part is intact, no oxide scale is generated, no local corrosion points are present, and the oxidation weight gain rate is 0.0056 g / (m 2 ·h), belonging to the completely oxidation-resistant level and possessing excellent ultra-high-temperature oxidation resistance. Description of the Drawings

[0046] Figure 1 . The Hull cell for testing.

[0047] Figure 2 . The front and back of the Hull cell test.

[0048] Figure 3 . Appearance diagrams of electroplating on the nickel-based alloy K414 alloy with two bath solutions.

[0049] Figure 4 . Microscopic morphology of the electroplated platinum surface, where: a - microscopic morphology of the electroplated platinum surface with the bath solution; b - cross-sectional microscopic morphology.

[0050] Figure 5 . Microscopic morphology of the deposited platinum layer and the platinum-aluminum bonding layer after thermal diffusion.

[0051] Figure 6 . Change process of the test piece during high-temperature oxidation.

[0052] Figure 7 . Oxidation weight gain curve of the IC21 / Pt diffusion test piece at 1150°C / 100 h heat resistance test.

[0053] Figure 8 . IC21 / PtAl specimen oxidation weight gain curve at 1150°C for 100 h.

[0054] Figure 9 . EDS elemental distribution map of the cross-section of the IC21 / Pt diffusion specimen. Detailed implementation methods

[0055] Example 1. Preparation of a small amount of "Q salt" intermediate

[0056] This reaction is carried out under the protection of an inert gas. Gas is generated during the reaction process, and it is necessary to promptly extract it from the reaction system.

[0057] Weigh 5.18 grams (0.01 mol) of H2PtCl6·6H2O, add 100 grams (5.56 mol) of distilled water to dissolve it, add 6.8 grams (0.08 mol) of KNO2, and boil until the solution color turns to hay color; after cooling, add a dilute solution containing 2.94 grams (0.03 mol) of phosphoric acid, stir and react at 80°C for 3 h, and the solution turns to hay color; concentrate the mother liquor to obtain a bright red precipitate, wash it with distilled water until there are no impurity ions, and keep the red precipitate in a moist state for standby;

[0058] Adjust the above-mentioned moist red insoluble matter into a 50 mL suspension, add 1.33 grams (0.02 mol) of acidified ammonium dihydrogen phosphate dilute solution, stir and react at 80°C for 3 h, the solution turns to hay color, rotary evaporate to remove most of the water, filter and take the filter cake, wash it 3 - 4 times with a small amount of ice water, and then vacuum dry at 60°C to obtain 3.12 grams of white powdery substance, with a yield of 96%; the chlorine content is 220 ppm.

[0059] Structural data: (1) The chlorine content of impurity elements < 5 ppm; (2) Elemental analysis: The measured values of Pt 59.8%, H 2.65%, N 8.80%, P 9.33% are consistent with the theoretical values of Pt 60%, H 2.15%, N 8.61%, P 9.53%. (2) MS-ESI + m / z: 229 ([M - Pt(NH3)2 + )). (3) 31 P-NMR (500 MHz, D2O) δ (ppm): 2.52, which conforms to the main characteristic atomic group absorption peak of [Pt(NH3)2](HPO4).

[0060] Example 2. Batch preparation of "Q salt" intermediate

[0061] This reaction is carried out under the protection of an inert gas. Gas is generated during the reaction process, and it is necessary to promptly extract it from the reaction system.

[0062] Weigh 518 g (1 mol) of H2PtCl6·6H2O, add it to 3 kg (167 mol) of distilled water and dissolve. Then add 680 g (8 mol) of KNO2 and boil until the solution color turns to withered grass color. After cooling, add a dilute solution containing 294 g (3 mol) of phosphoric acid. Stir and react at 80 °C for 3 h, and the solution turns to withered grass color. Concentrate the mother liquor to obtain bright red precipitate, wash it with distilled water until there are no impurity ions, and keep the red precipitate in a moist state for standby.

[0063] In a 20 L reaction kettle, adjust the above-mentioned moist red insoluble matter into a 5 L suspension, add a dilute solution of 133 g (2 mol) of ammonium dihydrogen phosphate acidified. Stir and react at 80 °C for 3 h, the solution turns to withered grass color. Rotate and evaporate to remove most of the water, filter and take the filter cake, wash it with a small amount of ice water to obtain a white crystalline solid, and dry it under vacuum at 60 °C to obtain 318 g of white powdery substance, with a yield of 97.84%; the chlorine content is 210 ppm.

[0064] Structure data: (1) Chlorine content of impurity elements < 5 ppm; (2) Elemental analysis: The measured values of Pt 59.8%, H 2.65%, N 8.80%, P 9.33% are consistent with the theoretical values of Pt 60%, H 2.15%, N 8.61%, P 9.53%. (2) MS-ESI + m / z: 229 ([M-Pt(NH3)2 + )。(3) 31 P-NMR (500 MHz, D2O) δ (ppm): 2.52, which conforms to the main characteristic atomic group absorption peak of [Pt(NH3)2](HPO4).

[0065] Example 3. Batch preparation of "Q salt"

[0066] Weigh 1000 g (5.102 mol) of the "Q salt" intermediate containing platinum into a 50 L reaction kettle, add 10 L of distilled water to dissolve it, then add 50 mL of 25% concentrated ammonia water, stir at 80 °C for 1 h, continue heating to remove the excess ammonia until pH≈7, filter to remove a small amount of insoluble matter, add distilled water to the filtrate, and control the total weight of the solution to be 25 Kg. The platinum content of the obtained Q salt aqueous solution is 4%, and the appearance is a colorless and transparent solution. After detection, the chlorine content < 3 ppm.

[0067] Example 4. Batch preparation of "P salt"

[0068] Weigh 1000 g (5.102 mol) of platinum-containing “Q salt” intermediate into a 50 L reactor. After adding 10 L of distilled water to dissolve it, add 2 L of an aqueous solution containing 870 g (10.24 mol) of KNO2. Stir at 50 °C for 2 h. After cooling to room temperature, filter, wash the filter cake with distilled water 3 - 4 times, and dry it under vacuum at 60 °C to obtain 1630 g of a pale yellow powdery substance with a yield of 99.01%; the chlorine content is detected to be < 3 ppm.

[0069] Example 5. Testing the electroplating ability of the initial solution

[0070] According to the existing bath formula: potassium citrate 25 g / L, ammonium hydrogen phosphate 20 g / L, potassium hydrogen phosphate 100 g / L, bath temperature 70 - 90 °C, current density (0.3 - 1) A / dm 2 , take 100 mL of the above-mentioned [{Pt(NH3)2}(HPO4)]2 solution, dissolve the raw materials with distilled water and adjust to 1 L for standby.

[0071] Take the above bath and conduct tests using a Hull cell. Use a copper-zinc alloy sheet as the cathode and a platinum-coated titanium mesh as the anode. The testing equipment is as Figure 1 shown.

[0072] Under high and low current density conditions, the deposited layer is evenly dispersed and has a moderate thickness; the current density covering ability of the bath is strong, and there is no local area with missed plating; there is a coating on the back of the test piece, indicating that the bath prepared with this platinum salt has strong throwing power, as Figure 2 shown.

[0073] Example 6. Heat resistance and long-term stability of the bath

[0074] Set the bath temperature to 85 °C in a constant temperature water bath, keep it warm for 8 h every day, simulate the state of long-term electroplating, and evaluate the stability and heat resistance of the bath by examining the color change of the bath, whether there is precipitation, and the substances deposited on the anode.

[0075] After the bath has undergone continuous production for more than 18 months, similar to other +2 platinum salts (“P salt” and “Q salt”) in alkaline baths, a yellow substance will cover the surface of the anode after long-term operation. This substance has a certain solubility in water, causing the color of the bath to gradually turn yellow. The reason may be that Pt 2+ is oxidized to PtO2·xH2O, and this oxide forms yellow-green [Pt(OH)6] in an alkaline environment 2- , but the bath does not produce black precipitation and has high transparency. Therefore, under this formula and process conditions, the bath has good heat resistance and stability, and the risk for large-scale continuous electroplating production is relatively low.

[0076] Example 7. Evaluation of Coating Appearance, Area and Microtopography

[0077] The concentration of platinum salt was adjusted to 2 g / L, and platinum of about 1 μm was deposited on a K414 alloy specimen with a size of φ2.5 cm × 2.5 cm × 2 mm. The thickness of the deposited platinum layer was measured by an XRF coating thickness gauge, and the appearance and area of the coating were observed and recorded visually and with the aid of a magnifying glass. The appearance results are as Figure 3 shown. It can be seen from the figure that the platinum layer deposited by the bath solution on the K414 alloy specimen is uniformly silver-white as a whole, without common electroplating defects such as peeling, blistering, ablation, and abnormal color.

[0078] Taking "GB / T 17722 Scanning Electron Microscopy Measurement Method for Metal Coating Thickness" as the reference standard, SEM was used to observe the surface microtopography and cross-section microtopography of the deposited platinum layer. The obtained coating is stable, the surface is flat and dense. Except for a small number of micropores, no defects such as cracks and inclusions were found. The uniformity of the coating cross-section is excellent, and no through longitudinal cracks were seen. (Except for the damage to the coating caused by wire electrical discharge machining during sample preparation), the results are as Figure 4 shown.

[0079] Example 8. Heat Resistance Evaluation of Deposited Platinum Layer and Platinum-Aluminum Bonding Layer after Thermal Diffusion

[0080] Taking "HB 5258-2000 Test Method for Determination of Oxidation Resistance of Steel and Superalloys" as the standard, a platinum layer of about 3 μm was deposited on a nickel-based single-crystal superalloy IC21, and then aluminized by gas phase to prepare an IC21 / PtAl coating specimen. The specimen was placed in a corundum crucible and taken out regularly for weighing and observation at 1150 °C for continuous operation for 100 h. Three groups of parallel experiments were carried out, and the IC21 / Pt specimen without aluminization was used as the control group to evaluate the oxidation resistance of the coating respectively. The oxidation resistance of the platinum-aluminum bonding layer was evaluated by macroscopic observation and SEM methods. The results are as Figure 5 .

[0081] The thickness of the deposited platinum layer of the IC21 / Pt specimen before aluminization was 15.85 μm, and the coating density was relatively high. When the matrix and the deposited platinum layer diffused with each other, the diffusion rate between the coatings was relatively low.

[0082] IC21 / Pt specimen heat resistance macroscopic appearance and oxidation weight gain data: The oxidation weight gain rate of the specimen is 0.985 g / (m 2 ·h), belonging to the oxidation resistance level; after 20 - 60 h of high-temperature oxidation, the specimen showed serious deterioration, and the Ni on the surface of the specimen was gradually oxidized into nickel oxide and other cyan powders, as Figure 6 .

[0083] After aluminizing, the surface grains of the IC21 / Pt specimen grow, the interfacial fusion degree between the matrix and the deposited layer is higher, the alumina film on the specimen surface is complete, no scale is generated, no local corrosion points, and the oxidation weight gain rate is 0.0056 g / (m 2 ·h), belonging to the complete oxidation resistance level, having excellent ultra-high temperature oxidation resistance, and the high temperature oxidation resistance of the prepared platinum aluminide coating meets the usage requirements.

[0084] In addition, when the coating faces high temperature oxidation conditions, an oxide film is formed on the alloy surface, preventing oxygen from further diffusing into the alloy interior. Compared with the original sample before diffusion, the average Pt content in the interdiffusion layer is about 18.91%, which not only enhances the adhesion between the oxide film and the matrix, stabilizes the alumina film, but also prevents the volatilization of refractory solid solution elements such as W and Mo in the alloy interior, thereby improving the oxidation resistance of the alloy. The results are as Figures 7 - 9 , among which Figure 9 the EDS element distribution of the cross-section of the IC21 / Pt diffusion specimen in

[0085] Region Ni (at.%) Pt (at.%) Al (at.%) Cr (at.%) Co (at.%) 1 43.43 17.60 6.04 16.65 14.70 2 33.49 22.44 14.57 2.93 5.81 3 53.12 16.69 14.81 2.97 6.13 .

Claims

1. A method for synthesizing a Q-salt intermediate, characterized in that, The Q-salt intermediate is a mononuclear diammineplatinum intermediate. Only 2 of the four hybrid orbitals of platinum in this intermediate are coordinated with ammonia, and the remaining 2 are empty orbitals. The charge is balanced by hydrogen phosphate outside. Its molecular formula is [Pt(NH3)2](HPO4), and its structural formula is: ; The synthesis method includes: Step 1, synthesize the binuclear platinum complex [{Pt(NH3)2}(HPO4)]2: Weigh a certain amount of chloroplatinate, dissolve it in distilled water, then add nitrite, and boil until the solution color turns to withered grass color; after cooling, add dilute phosphoric acid solution, stir and react at 80 °C for 3 h, and the solution color turns to withered grass color again. Concentrate the mother liquor to obtain a bright red precipitate, wash it with distilled water until there are no impurity ions, and keep the red precipitate in a moist state for standby; Step 2, synthesize the mononuclear diammineplatinum intermediate [Pt(NH3)2](HPO4): Take the moist red precipitate from Step 1, add a certain amount of dilute ammonium dihydrogen phosphate solution acidified, react until the red solid completely dissolves into a withered grass color solution, rotary evaporate to remove a large amount of solvent, filter, take the filter cake, wash it with a small amount of ice water to obtain a white crystalline solid, and vacuum dry it at a certain temperature to obtain the target intermediate.

2. The synthesis method of the Q salt intermediate according to claim 1, wherein, The binuclear platinum complex [{Pt(NH3)2}(HPO4)]2 has a structure in which the oxygen of the polybasic oxyacid directly coordinates with platinum, and the polybasic oxyacid therein is sulfate or carboxylate.

3. The synthesis method of the Q salt intermediate according to claim 1, characterized in that, In step one, [PtCl6] 2- : NO2 - : the molar ratio of the dilute acid is 1:6 to 10:1; in step two, the molar ratio of platinum to ammonium dihydrogen phosphate is 1:1 to 4.

4. The synthesis method of the Q salt intermediate according to claim 1, characterized in that, In Step 1, the chloroplatinate includes any one of H2PtCl6·6H2O, K2PtCl6, and Na2PtCl6.

5. The synthesis method of the Q salt intermediate according to claim 1, characterized in that, In Step 1, the reaction is carried out under an inert gas, and the gas discharged at the beginning of the reaction needs to be discharged from the system in time.

6. A method for preparing Q salt using a Q salt intermediate, characterized in that, Include: Take a certain amount of the Q-salt intermediate synthesized by the synthesis method of a Q-salt intermediate described in any one of claims 1-5, add a certain amount of ammonia water, stir at a certain temperature for 1 h, heat to remove the excess ammonia, adjust the pH to neutral, and dilute with water until the platinum content is 2% - 4% to obtain the aqueous solution of the Q-salt.

7. The method for preparing Q salt using a Q salt intermediate according to claim 6, characterized in that, The molar ratio of platinum to ammonia water is 1:4 - 10.

8. A method for preparing P salt using Q salt intermediate, characterized in that, Include: Take a certain amount of the Q-salt intermediate synthesized by the synthesis method of a Q-salt intermediate described in any one of claims 2-5, add a certain amount of nitrite, stir at a certain temperature for 1 h, cool to room temperature, filter, wash the filter cake with distilled water, and vacuum dry the filter cake at a certain temperature to obtain a white or light yellow-green P-salt solid.

9. The method for preparing P salt from Q salt intermediate according to claim 8, characterized in that, The molar ratio of platinum to nitrite is 1:2 - 10.

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