CN101503811A - Method for electroplating shaft bushing antifriction layer by metilsulfate plating bath - Google Patents

Abstract

The invention relates to a method for plating a bush antifriction coating through a methyl sulfonate bath. The method comprises the following steps: (1) cleaning a bush after ultrasonic degreasing, and cleaning a bush upper ring after cathode electroplating degreasing; (2) cleaning the bush after dilute hydrochloric acid activation for 1 to 2 minutes, placing the bush into the methyl sulfonate bath, taking a terne metal containing 10 percent of tin as an anode at a room temperature, carrying out the electroplating for 18 to 22 minutes when the cathode current density is 2 to 3 A/dm<2>, and then cleaning the bush and obtaining a terne copper coating on the inner surface of the bush; and (3) placing the bush into a tinning bath, taking a steel plate as an anode at 75 to 80 DEG C, carrying out the electroplating for 3 to 8 minutes when the cathode current density is 1 to 1.5 A/dm<2>, and obtaining a tin coating on the inner surface of the bush. The methyl sulfonate bath has stable performance and a simple process; the coating has fine crystallization, good hardness and good abrasion resistance; the bush coating has even thickness; as no strong complexing agent and F<-> are contained, wastewater is easily processed; and the method is suitable for plating the bush antifriction coating on large and medium-size diesel engines and combustion engines.

Description

The method of electroplating shaft bushing antifriction layer by metilsulfate plating bath

Technical field

The present invention relates to a kind of big-and-middle-sized diesel engine, internal combustion engine bearing ware reducing coating layer electroplating technology, specifically be meant a kind of method that adopts environment-friendly type metilsulfate plating bath electroplating shaft bushing antifriction coating.

Background technology

The Pb-Sn-Cu ternary alloy coating is widely used in big-and-middle-sized diesel engine, internal combustion engine bearing antifriction layer owing to have performances such as good compactness, solidity to corrosion, wear resistance and fatigue resistance.The electroplating technology of existing Pb-Sn-Cu ternary alloy anti-attrition coating all adopts the fluoroborate bath system, and there are some defectives in its plating bath, as the plating bath instability, need prevent that tin atom is to the diffusion of matrix in the alloy layer with the nickel plating grid, yield rate is low, is not suitable for serialization production in enormous quantities; And because of the feasible Pb that contains of the strong complexing action of fluoroboric acid ²⁺, F ^-Poisonous wastewater treatment very difficult, the wastewater treatment expense is high and be difficult to realize qualified discharge, the harm environment, existing in recent years a plurality of countries and regions ban use of the electroplating technology of fluoroborate plating bath.

Summary of the invention

Purpose of the present invention just provides a kind of method that adopts the electroplating shaft bushing antifriction layer by metilsulfate plating bath of safety non-toxic environment-friendly type.

The applicant draws by test: concentration of metal ions to the Coating composition influence significantly in the metilsulfate plating bath.When other conditions are constant, improve slicker solder cupric ion concentration separately, slicker solder copper content all obviously rises in the alloy layer.By adjusting the coating that slicker solder cupric ion in the metilsulfate plating bath can obtain different slicker solder copper ratios, increase free methylsulphonic acid concentration, the content of coating tin descends to some extent, and quality of coating obviously descended when free methylsulphonic acid concentration was big.Gelatin can make coating smooth careful even, and Resorcinol can be stablized the plating bath effect, suppresses Sn ²⁺→ Sn ⁴⁺Transform, can also reduce coating fragility, make coating smooth careful; But along with the content of gelatin or Resorcinol increases, the content of tin also increases in the coating, and the content of copper then descends to some extent.

The present invention can realize in the following manner: clean after the oil removing of (1) bearing shell ultrasonic wave, hang on the bearing shell and carry out cleaning after negative electrode is electroplated oil removing; (2) the bearing shell volume ratio is to clean behind the dilute hydrochloric acid activation 1～2min that is made at 1: 3, and bearing shell is put into the metilsulfate plating bath, at room temperature makes anode with the terne metal of stanniferous 10%, cathode current density 2～3A/dm ²To cleaning behind inner surface of bearing bush plating 18～22min, inner surface of bearing bush obtains the slicker solder copper coating; (3) bearing shell that internal surface is coated with the slicker solder copper coating puts into that to contain sodium hydroxide be 10g/L, contain the tin plating electrolyte that sodium stannate is 85g/L, makes anode at 75～80 ℃ of lower steel plates, and cathode current density is 1～1.5A/dm ²The monoblock bearing shell is electroplated 3～8min, and bearing shell obtains tin coating on the surface.

The metilsulfate electroplate liquid formulation is to contain methylsulphonic acid 110～145g/L, methylsulphonic acid lead with Pb in the above-described step (2) ²⁺Meter 85～110g/L, stannous methanesulfonate are with Sn ²⁺Meter 8～14g/L, copper methanesulfonate are with Cu ²⁺Meter 1.5～4g/L, gelatin 2～5.5g/L, Resorcinol 5～8g/L.

Metilsulfate plating solution performance of the present invention is stable, electroplating technology simply need not the electronickelling grid, the coating crystallization is careful, hardness good, wear resisting property is good; Cooperate the frock hanger can make the lower bearing shell thickness of coating even, need not precision work after the plating, be fit to produce in enormous quantities; The metilsulfate plating bath is not owing to contain strong complexing agent and F ^-, waste water is handled qualified discharge easily, is applicable to big-and-middle-sized diesel engine, oil engine electroplating shaft bushing antifriction layer.

Embodiment

Below in conjunction with embodiment, the present invention is described in further detail, but it is not represented as unique embodiment of the present invention.

The present invention uses methylsulphonic acid, methylsulphonic acid lead, stannous methanesulfonate, copper methanesulfonate concentrated solution, and their concentration is respectively: $M_{{\mathrm{CH}}_3{\mathrm{SO}}_{3}H}=960g/L,$ $M_{\mathrm{Pb}{\left({\mathrm{CH}}_3{\mathrm{SO}}_3\right)}_2}=905g/L,$ $M_{\mathrm{Sn}{\left({\mathrm{CH}}_3{\mathrm{SO}}_3\right)}_2}=785g/L,$ $M_{\mathrm{Cu}{\left({\mathrm{CH}}_3{\mathrm{SO}}_3\right)}_2}=450g/L.$

Typical metilsulfate plating bath preparation: adding concentration in the 1 parts by volume metilsulfate plating bath successively is methylsulphonic acid strong solution 0.145 parts by volume of 960g/L, methylsulphonic acid lead solution 0.223 parts by volume that concentration is 905g/L, stannous methanesulfonate solution 0.03 parts by volume that concentration is 785g/L, methylsulphonic acid copper solutions 0.022 parts by volume that concentration is 450g/L, gelatin solution 0.2 parts by volume that concentration is 20g/L, Resorcinol solution 0.1 parts by volume that concentration is 65g/L, stir with distilled water diluting to 1 parts by volume at last, promptly obtain the metilsulfate plating bath.

Embodiment one

Two-sided lead plating stannum copper alloy coating on the platinized platinum that specification clean by oil removing and that weigh is 3 * 4cm.Convert dilute hydrochloric acid activation 1～2min that 3 volume water are made into 1 volume concentrated hydrochloric acid, the platinized platinum water after the activation cleans, then with above-mentioned metilsulfate plating bath at room temperature anode be the terne metal of stanniferous 10%, cathode current density 2.5A/dm ², platinized platinum is carried out two-sided plating 20min, obtain the uniform and smooth fine and close slicker solder copper coating in surface.Prepared platinized platinum slicker solder copper coating is thickness 22 μ m after measured, and the slicker solder copper coating is through dissolving and volumetry coating content with acid: tin 7.8%, copper 2.3%, plumbous 89.9%.

Embodiment two

The pot metal inner surface of bearing bush that is 490QZL to 15 specifications simultaneously on the frock hanger is electroplated the slicker solder copper coating.Bearing shell is first to be 12g/L with containing NaOH, contain Na ₂CO ₃For 25g/L, contain Na ₃PO ₄12H ₂O is 60g/L, contain Na ₂SiO ₃Be the degreasing fluid of 12g/L, under 50 ℃ of temperature, carry out ultrasonic wave oil removing 5min; Go up to hang after the oil removing of bearing shell ultrasonic wave with containing NaOH be 12g/L, contain Na ₂CO ₃For 25g/L, contain Na ₃PO ₄12H ₂O is 35g/L, contain Na ₂SiO ₃For the electrolytic degreasing liquid of 7g/L, at room temperature make anode, cathode current density 2.5A/dm with steel plate ²Carry out electrolytic degreasing 4min; After bearing shell oil removing is for the second time cleaned, be that 1: 3 dilute hydrochloric acid promptly activates 1min with the dilute hydrochloric acid that 1 volume concentrated hydrochloric acid and 3 volume water are made into volume ratio; Put into 60 after bearing shell after the activation cleans and go up and state the metilsulfate plating bath, at room temperature make anode, cathode current density 2A/dm with the terne metal of stanniferous 10% ²Inner surface of bearing bush is electroplated 22min, obtain canescence slicker solder copper coating, the uniform and smooth densification of coating surface, the bearing shell thickness of coating is 21～23 μ m.

After inner surface of bearing bush is electroplated the slicker solder copper coating, be 10g/L with containing NaOH, contain Na ₂SnO ₃Be the tin plating electrolyte of 85g/L, make anode at 75 ℃ of lower steel plates, cathode current density is 1A/dm ²The monoblock bearing shell is electroplated 8min, and the bearing shell surface obtains silvery white zinc-plated protective layer, and the surface is uniform and smooth, thickness 1～2 μ m.

Embodiment three

Lead plating tin copper coating on the pot metal inner surface of bearing bush that is 490QZL to 45 specifications simultaneously on the frock hanger.Bearing shell is first to be 12g/L with containing NaOH, contain Na ₂CO ₃For 25g/L, contain Na ₃PO ₄12H ₂O is 60g/L, contain Na ₂SiO ₃Be the degreasing fluid of 12g/L, under 60 ℃ of temperature, carry out ultrasonic wave oil removing 5min; Go up to hang after the oil removing of bearing shell ultrasonic wave with containing NaOH be 12g/L, contain Na ₂CO ₃For 25g/L, contain Na ₃PO ₄12H ₂O is 35g/L, contain Na ₂SiO ₃For the electrolytic degreasing liquid of 7g/L, at room temperature make anode, cathode current density 2.5A/dm with steel plate ²Carry out catholyte oil removing 5min; After bearing shell oil removing is for the second time cleaned, be that 1: 3 dilute hydrochloric acid activates 2min with volume ratio; Put into 60 after bearing shell after the activation cleans and go up and state the metilsulfate plating bath, at room temperature make anode, cathodic current 2.5A/dm with the terne metal of stanniferous 10% ²Inner surface of bearing bush is electroplated 18min, obtain canescence slicker solder copper coating, the uniform and smooth densification of coating surface, thickness is 21～23 μ m.

After inner surface of bearing bush is electroplated the slicker solder copper coating, be 10g/L with containing NaOH, contain Na ₂SnO ₃Be the tin plating electrolyte of 85g/L, make anode at 80 ℃ of lower steel plates, cathode current density is 1.5A/dm ²The monoblock bearing shell is electroplated 3min, and the bearing shell surface obtains silvery white zinc-plated protective layer, and the surface is uniform and smooth, thickness 1～2 μ m.

Claims (2)

1, a kind of method of electroplating shaft bushing antifriction layer by metilsulfate plating bath is characterized in that:

(1) cleans after the oil removing of bearing shell ultrasonic wave, hang on the bearing shell and carry out cleaning after the catholyte oil removing;

(2) the bearing shell volume ratio is to clean behind the dilute hydrochloric acid activation 1～2min that is made at 1: 3, and bearing shell is put into the metilsulfate plating bath, at room temperature makes anode with the terne metal of stanniferous 10%, cathode current density 2～3A/dm ²To cleaning behind inner surface of bearing bush plating 18～22min, inner surface of bearing bush obtains the slicker solder copper coating;

(3) bearing shell that internal surface is coated with the slicker solder copper coating puts into that to contain sodium hydroxide be 10g/L, contain the tin plating electrolyte that sodium stannate is 85g/L, makes anode at 75～80 ℃ of lower steel plates, and cathode current density is 1～1.5A/dm ²The monoblock bearing shell is electroplated 3～8min, and the bearing shell surface obtains tin coating.

2, the method for electroplating shaft bushing antifriction layer by metilsulfate plating bath according to claim 1 is characterized in that the metilsulfate electroplate liquid formulation is to contain methylsulphonic acid 110～145g/L, methylsulphonic acid lead with Pb in the step (2) ²⁺Meter 85～110g/L, stannous methanesulfonate are with Sn ²⁺Meter 8～14g/L, copper methanesulfonate are with Cu ²⁺Meter 1.5～4g/L, gelatin 2～5.5g/L, Resorcinol 5～8g/L.