JPS61217583A - Phosphating method - Google Patents

Abstract

PURPOSE:To improve the lubricity of a member to be worked during cold working by forming a phosphate film on the surface of the member in a phosphate soln. of a prescribed acidity contg. NO3<->, F<-> and BrO3<-> as an accelerator so that a stearate film to be formed on the phosphate film is adhered to the phosphate film. CONSTITUTION:A phosphate soln. of <=100 Pt total acidity TA contg. NO3<->, F<-> and BrO3<-> and/or NO2<-> as an accelerator is prepd. A phosphate film is formed on the surface of a member to be worked in the phosphate soln. A stearate film is then formed on the phosphate film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a phosphate chemical conversion treatment method for forming a phosphate film on the surface of a workpiece to facilitate cold working. be.

[Prior Art] Conventionally, in order to form this kind of phosphate film on the surface of a wire, the total acidity TA in the phosphate Zn (H2PO4)2 treatment bath was set to 50 pt, and an oxidizing agent was used as an accelerator. -NO
a-1NO2″″, C 03″″, metal ion-C12
+, Ni2÷, C02 age, Moasha, organic acid-EDTA
1 or a surfactant, etc., and the processing time is 5~5~
It was set to about 15 minutes.

By the way, as a method of shortening this treatment time, a method of increasing the total acidity TA to 100 pt or more is known.

[Problems to be Solved by the Invention] However, in this method, many crystals grow in the direction perpendicular to the workpiece, so even if a stearic acid film is formed thereon, the adhesion of the film is poor. There was a problem that the lubrication effect during cold working was poor.

The present invention has been made in order to solve the problems of the above-mentioned conventional technology, and uses phosphoric acid that adheres closely to the workpiece through a short-time film forming treatment and that exhibits excellent ljl lubricating properties during cold working. The object of the present invention is to provide a phosphate chemical conversion treatment method that forms a salt film.

[Means for Solving the Problems] The present invention, which has been made to achieve the above object, provides a phosphoric acid film that forms a phosphate film on the surface of a workpiece and further a stearate film on the phosphate film. In the salt conversion treatment method, the phosphate film is treated with NOs-, F-, BrO'; or N in a phosphate solution with a total acidity TA≧100pt.
It is characterized by being formed in a solution using an accelerator containing at least one of Ox-.

Here, the phosphate film is Zna(POa)z・4H
20, Zn Fe (POa)2 ・4HzO1zn
2 Ca (POa)2 ・2HzO etc.
The total acidity refers to the 1.1 number of NaOH when the phosphate conversion solution 101 is titrated with 1/1ON NaOH using phenolphthalein as an indicator.

[Function] NO3-, F-, B'03- or NO
3Zn (H2PO
4) 2+4H20? IZns (POa)2
・4H20↓+4HiP(% reaction, Zn5(POa)z・4H20 is precipitated on the surface of the workpiece.

Next, the phosphoric acid dissociated in the above reaction dissolves Fe on the surface of the workpiece, that is, Fe +2Hs
The reaction POa→Fe (H2POa)2+2H occurs, and this l”e N(2PO4)
2 and 7n (H2POa)z react to form 1”e
(H2PO4)z+2Zn (H2PO4)Z+4
HzO-+Zn2Fe (POa)2 ・4Hz
O↓+4HsPOa, Zn 2 Fe (POa)2 ・4HzO
is deposited on the surface of the workpiece.

The reaction ends when a phosphate film is formed on the entire surface of the workpiece.

In the above reaction, NOs −
Since 1N Ox- or 3ro3-1F- is added, a phosphate film that adheres quickly and quickly is formed on the surface of the workpiece.

Therefore, since the stearate film in the post-treatment is formed densely, lubrication can be smoothly performed during cold working.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

A 80M435 10φ test material was used as the workpiece, and the conditions for the chemical conversion treatment solution were a total acidity of TA-2.
Using Zn (H2PO4)2 phosphate at 00+1t, and further NO3-1NO2-13r Os-,F
- Add an accelerator consisting of a combination of
A phosphate film of about ~15 μm was formed. Next, under the conditions of a sodium stearate concentration of 4.2ml/k% and a liquid temperature of 1180°C, 111Zn of stearin with a thickness of about 0.5 to 2μ and further a sodium stearate film were formed. Table 1 shows the results of film performance with respect to the type of accelerator.

Table 1 [ [ In Table 1, the evaluation of film performance is 1111! Using a coefficient testing machine, the surface of the test material was subjected to line contact with a load equivalent to 5 kO, and the number of times of sliding when the film on the surface of the test material peeled off was calculated based on the conventional film formation method. It was expressed as the ratio of the number of calendar movements during which the formed film was peeled off.

Originally, the purpose is to improve the lubricity of the film during cold working, so it is desirable to test the peeling state of the film in a forward extrusion test where the same force as in extrusion is applied to the film, for example, As shown in FIG. 8, the evaluation of the limit WI rib count by the II friction coefficient tester and the evaluation of the peeling state of the film by the forward extrusion tester are in close agreement, so the VII friction coefficient tester was used instead.

In addition, as a comparative example corresponding to the conventional technique, a total acidity of TA-50pt, N was obtained using a commercially available phosphorylated solution.

The treatment was carried out at a concentration of 2-0.006% by weight, a treatment time of 5 minutes, and a liquid temperature of 80°C. Table 1 shows the results based on this film performance.

As is clear from the results shown in Table 1, NOx-
1Boa''', F- combination, N0a-1NO2-, F
-, EDTA combination and NO3-1B r Oa
The film performance was improved for the combinations of '-, F-, and EDTA.

Next, based on the results of the above examples, it is desirable that each component of the chemical conversion treatment solution meet the following conditions.

(1) Total acidity TA As shown in Figure 1, as a result of film formation treatment with TA-50 and TA-150, the skin Hi! The amount increases in a shorter time when the total acidity is higher, and as shown in Figure 2, when the treatment time is 1 minute and the total acidity is changed, the film weight increases when the total acidity is higher. was found to be high. Therefore, when performing the film treatment in a short period of 11t (within 1 minute), it is desirable that TA≧100.

(2) The action and concentration of NOa″″ NO3- has the effect of oxidizing Fe2÷ in the phosphate chemical solution to l″e″, and its 11 degrees are shown in Figure 3. As shown, the weight of the film becomes constant between 1 and 5%, so this concentration t! Preferably.

(3) Effects and concentration of NO2-, Br Os- and NO2
″″ and BI'03- both have strong oxidizing effects,
It has the effect of accelerating the reaction by oxidizing and removing hydrogen atoms generated on the surface of the sample material. NO2″″ and B
Since rO3'' has the same effect, either one may be added.

As shown in Figure 4, 1NOz at 2.5% by weight NOs-
-, it takes 0.0 to produce the effect. O05 city ffi% or more is required, while the concentration is 0.
If it exceeds 0.015% by weight, the phosphoric acid film on the surface of the sample material becomes too fine and the weight of the film decreases.

On the other hand, as shown in Figure 5, when only BrO3- is added under 2.5 wt% NOJ, 0.8 wt%
Due to the above, sludge adheres to the surface of the sample material, so 0.8
It is preferably 0.01 to 0% by weight or less, particularly preferably 0.01 to 0.
．． It is 5% by weight.

(4) The effect of F- and the concentration F″″ have the effect of corroding the surface of the sample material, thereby promoting the formation of a film. As shown in Figure 6, F'''' tends to decrease the film weight as its concentration increases, but it does not have much effect on the film performance itself, and the concentration range is preferably 0.01 to 1 weight. performance%.

(5) Effect and concentration of EDTA EDTA has the effect of suppressing the growth of the phosphate film in the direction perpendicular to the surface of the test material, and therefore has the effect of making the film adhere to the test material. As shown in FIG. 7, the concentration range is preferably less than 2% by weight because if it exceeds 2% by weight, the amount of film will decrease.

[Effects of the Invention] As explained above, according to the present invention, a film can be formed in close contact with the workpiece by a short film forming treatment, and an excellent lubrication effect can be achieved during cold working. I can do it.

[Brief explanation of the drawing]

Figures 1 to 7 are graphs showing the relationship between skin age and various parameters, Figure 1 is a graph showing the relationship with treatment time, Figure 2 is a graph showing the relationship with total acidity, and Figure 2 is a graph showing the relationship with total acidity. Figure 3 is a graph showing the relationship with NOa'' concentration, Figure 4 is a graph showing the relationship with NOx concentration.
-'A graph showing the relationship with degree, Figure 5 is BPO4-I
Fig. 6 is a graph showing the relationship with F'''' concentration, Fig. 7 is a graph showing the relation with EDTA 11 degrees, Fig. 8 is the graph showing the relationship with EDTA 11 degrees, and Fig. 8 is the graph showing the relationship with F'''' concentration. It is a graph showing correlation of evaluation.

Claims (1)

[Claims] In a phosphate chemical conversion treatment method in which a phosphate film is formed on the surface of a workpiece and a stearate film is further formed on the phosphate film, the phosphate film has a total acidity TA≧ In 100pt phosphate solution, NO_3^-, F^- and BrO_3^
- or NO_2^- in a solution using an accelerator containing at least one of the following.