JPS6024198B2 - Manufacturing method of anode material for copper plating - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing an anode material for copper plating, and in particular a method for slowly cooling an oxygen-containing steel anode material containing at least about 0.1% by weight of oxygen from a temperature of 80,000 or higher. The present invention relates to a method for producing an anode material for copper plating which has significantly high dissolving activity and at the same time significantly reduces the amount of anode sludge produced. Currently, phosphorus-containing steel anodes are widely commercially available as anodes for bright steel plating. Phosphorus-containing steel anodes have good dissolution properties, but they require the handling of toxic phosphorus during manufacturing, the phosphorus elutes during the plating process and requires purification, and the voltage in the plating bath is relatively high. The results are not necessarily satisfactory in many respects. On the other hand, there have been attempts to improve the anodic dissolution characteristics of the copper base material by enriching it with oxygen, and although these efforts have been investigated from various angles, no success has yet been achieved. This is because enriching oxygen improves the dissolving activity of the anode material itself, which is good, but on the other hand, as the amount of oxygen in the anode increases, the amount of sludge produced increases to an extent that it is unusable. As for the properties of an anode for plating, it is particularly required that it not only have excellent dissolution properties but also have an anode sludge generation rate of less than 4. Recently, demands for improving the quality of the plating film and the workability of plating in copper plating have become increasingly severe, and as part of this, there is a strong demand for the development of copper anode materials with excellent properties. Anode materials for copper plating must meet at least the following requirements: '1} Excellent melting properties, ■ Low anode sludge generation rate (= amount of sludge generated / amount of molten steel), '31 Does not contaminate the finishing bath, ■ Slime film is formed on the anode surface. Since the voltage for plating becomes high, no slime film is formed.
'5} There should be no trouble in manufacturing the anode material. As mentioned above, research has already been conducted to improve the dissolution performance of Cu-○ based anodes by adding oxygen to copper, but the reason why these efforts failed is that the oxygen in the anode is The sludge exists in the form of a phase, and as the anode dissolves, a portion of this is liberated from the anode surface, unnecessarily increasing the amount of sludge produced. Therefore, if the adverse effects associated with the Cu20 phase can be removed, an extremely excellent copper anode material for copper plating that satisfies the above requirements should be obtained. The present inventor has developed a method using Cu2 while successfully utilizing its effect as a promoter to increase the dissolution activity of oxygen in the anode.
We have conducted repeated research to eliminate the negative effects of sludge generation associated with 0-phase. As a result, by slowly cooling the oxygen-containing copper anode material from a high temperature, at least a part of the C mountain ○ phase in the copper structure was reduced to a C ratio ○→
It has been found that an extremely effective method is to convert it into CuO according to the reaction formula: Cu○Cu0. Unlike the C3 phase, even if the Cu phase is released in the plating solution, it is easily leached out with acid without the aid of oxygen existing in the port, and the rate at which it remains as part of the sludge is very low. It becomes less. The higher the temperature at the start of slow cooling (800° C. or higher) and the slower the slow cooling temperature, the higher the activity of the Cu-0 anode and the higher the conversion efficiency of C. Here, this processing method will be referred to as "activation processing." For example, even if this activation treatment is applied to a material such as electrolytic copper whose oxygen content is extremely low (~side wind), there will be no effect at all. An important point of the present invention is to perform the activation treatment by slow cooling from a high temperature in the presence of a sufficient amount of oxygen. Thus,
The present invention provides a method for manufacturing a copper anode material used in a sulfuric acid steel plating solution, in which the steel anode material contains 0.1% by weight or more of oxygen, and the oxygen-containing copper anode material is heated at a temperature of 800°C or higher to 27,000°C. Provided is a method for producing an anode material for copper plating, characterized in that slow cooling treatment is performed at a cooling rate slower than / hour. The copper anode material used in the present invention is high purity steel such as electrical steel. The above-mentioned phosphorus-containing steel is also targeted because its properties can be further improved by applying this treatment, provided that the adverse effects caused by phosphorus, such as purification of the plating solution and handling of toxic phosphorus, can be adequately addressed. It can be. The molten copper is first subjected to oxygen enrichment treatment. This is carried out by blowing air, oxygen gas, etc., or by adding copper oxide (CO) powder. An appropriate amount of oxygen is added according to the oxygen enrichment target amount. The oxygen content must be 100 μm (0.1
It is desirable that the content be greater than 1% by weight, and the solubility characteristics improve as the content increases. However, when the temperature exceeds 650, a part of u20 is precipitated in the structure of the anode as dendrites without undergoing phase transformation to Cu○. Although the sludge production rate is maintained at 1% or less as shown in the examples below even when the oxygen content is above the above, there is no need to increase the oxygen content beyond this. Therefore, it is generally preferable to aim for an oxygen content in the range of 1,000 to 6,500. The oxygen-enriched copper hot water is molded and solidified into any shape, such as a plate, shot, ball, opal plate, etc., depending on the desired form of the anode material. The solidified oxygen-enriched anode material undergoes an activation treatment.
The activation treatment is carried out by slowly cooling the anode material before its temperature drops below 800°C, or in the case of anode material that has already cooled down, heating it to 80,000°C or higher and then slowly cooling it. . The slow cooling rate is 15-2700
The range is preferably 0/hour. If it is smaller than lyo/hour, the cooling time will be too long, which may cause problems during industrialization, and on the other hand, if the C ratio is larger than 27,000/hour, C
The phase transformation to u◯ is not sufficiently achieved and the required activation process cannot be achieved. If the temperature at the start of slow cooling is 8000° or less, no matter how the slow cooling rate is changed within the above range, the coarsening of crystal grains and the phase transformation of Cu20 to CI will not be sufficiently achieved, and the anode properties will not be as good. , it is not significantly improved. Usually, slow cooling is preferably started from a temperature of 800 to 105,000. The higher the temperature at the start of slow cooling (80,000 or higher) and the slower the slow cooling rate, the higher the conversion efficiency from C ratio ○ to C to 0, and the higher the activity of the Cu-○ anode. Slow cooling is carried out, for example, by placing the anode material in a furnace and lowering the furnace temperature, but it is desirable to maintain a non-oxidizing atmosphere using an inert gas such as nitrogen or argon. The slow cooling operation is performed for at least 300 hours, preferably for 200 minutes.
This may be continued until midnight, after which the anode material may be taken out of the furnace and rapidly cooled. The anode material thus treated is used as an anode for a sulfuric acid steel-based steel finishing bath. As mentioned above, the anode material subjected to the oxygen enrichment + activation treatment according to the present invention significantly increases the activity of anode dissolution compared to the untreated case, and at the same time reduces the amount of sludge generated by 1%.
The bottom will be much lower. Furthermore, since the anode material manufactured according to the present invention does not substantially form a slime film on the anode surface, a relatively thick slime layer having a composite composition of C*C*P*P205 is formed on the anode surface. Unlike the commercially available phosphorus-containing steel anode material that covers the anode, the voltage in the plating bath is lowered by, for example, 15 to 20%, and there is a great economic advantage during operation. No pollution occurs during operation. Example 1 First, high-purity deposited steel was obtained by electrolytic refining on a laboratory scale (composition, skin: ○=9, Ni<1, As=2.5Sb
<1, Se=0.6, Te<1, Sku5, Fe<1, B
i<0.1, Sn<0.1, Au<5, Ag=10). This was melted in an alumina crucible, and then an appropriate amount of Cu20 powder (reagent grade) was added to bring the oxygen concentration to 100-8.
, 800 blood. This molten copper was allowed to cool and solidify in a graphite mold, and then divided into two equal parts, one of which was left as-is and the other was heat-treated in an argon stream. In the heat treatment, after heating to 1,050 qo, simple slow cooling was continued at an average rate of 15 qo/h until the furnace temperature dropped to 15,000 qo, and then the material was taken out into the air and allowed to cool. Table 1 shows the oxygen spectroscopy results for a series of copper anode samples thus obtained. Table 1 (Adjacency value, ppm) The surface of each sample was machined to a size of 9 x 5 x 1.3, and then polished with emery paper up to #600, washed with water, and immediately after degreasing. An answer test was conducted. A pair of stainless steel cathodes housed in a cathode box were placed in the electrolytic chamber (3-capacity) used, and a test anode was placed in the center thereof. A piece of titanium coated with insulating tape was screwed into the upper end of each anode, and the entire electrode was immersed in the electrolyte and dissolved. Electrolysis conditions are current density 200A/W, liquid temperature 55
℃, and the electrolysis time was 40 to 4 hours. The composition of the electrolyte is 4 cough/SoCu, 2 female/SoNi, 20 female/Sunset 2S0
In Step 4, about 5% of a thiourea-based brightener (trade name: UBAC≠1), which is used in many copper glazing factories, was added. After the experiment was completed, all the generated anode sludge (at the bottom of the plating tank adhering to the anode surface) was collected, immediately washed with water and then washed with methanol, and then immediately placed in a desiccator and vacuum dried. It was assumed that the weighed sludge was mainly composed of copper powder Cuo and a phase with a C ratio of 0, and therefore, the amount of the phase with a C ratio of 0 was estimated based on the oxygen analysis value. The amount of sludge produced and the amount of Cu0 and C&○ in it are untreated,
Table 2 summarizes all the copper anode samples subjected to slow cooling. Table 2 A) Untreated B) Treated Further, a graph showing the relationship between the sludge production rate and the anode material oxygen content is shown in the drawings in addition to the data in Table 2. Combining these results, the following main conclusions can be drawn. [In the case of a' fertilization treatment, as the amount of oxygen increases in the hypoeutectic (Fig. 3) region, the amount of sludge produced also increases significantly.

[0]
= approximately 6.3% for 4,800 areas. Near the eutectic point, this value suddenly drops to nearly 1%, and eventually enters the hypereutectic region.

[0] Gradually continues to increase as it increases. 'b) Heat treatment results in a very low sludge production rate across the range of oxygen levels.

[0] = about 1 from 10Q fence and very low untreated anode
．． A sludge production rate of 8% was obtained, but there was almost no change even after heat treatment (please compare sample ship 1). 'c' However, when a method of adding oxygen and heat treatment is applied, the amount of sludge produced is considerably reduced.

[0] = 0.7% for 800 skin, from this

As [0] is increased, this continues to decrease further and the treated sample M. 4 ([0
]=390Q blood), the lowest value (0.07%) was recorded. Above this level, it remained almost constant in the range of 02 to 0.3%. 'd- Regarding the properties of the generated sludge,

[0] As the color increases, the brownish color gradually increases. This is because the content of C-yen gradually increases (see Table 2).
Also, the treated anode sample vessel mentioned in section c above. The sludge derived from Cu:0 is black and has a split value of 63.
The ratio is 54:14, which is rather close to the stoichiometric ratio of the Cu○ compound.
This is evidence that a phase transformation from C-◯➝Cu◯◯C has indeed occurred in the copper structure due to heat treatment. Example
2 Prepare small specimens of copper anodes as described in Example 1, heat them to 800qC, and immediately cool slowly (approximately 2700qC).
0/h). The results of the electrolytic test were as follows. From this, it can be seen that the spirit of the present invention cannot be fully realized if the child heat temperature is too low and the slow cooling rate is too high. However, in order to achieve a sludge production rate of nearly 1%, in the case of the present heat treatment conditions, it seems to be good if [0] is kept below about 2000 traces. Reference example 10.2 Shoes t. Make about 10k9 of steel shot enriched with %0 and put it into the anode basket (filling capacity about 1kg, filling rate 36%)
An electrolysis experiment was conducted. The conditions were as described in Example 1, and the experiment was terminated when 1293 g was dissolved, and the resulting sludge was collected, washed with water, dried, and weighed. The amount of sludge generated is 8. This is 6.4% for spots.
Corresponds to the sludge occurrence rate. Also, this sludge is Cuo
As a result of X-ray diffraction analysis, it was found that it contained 74% powder and 26% C uniform ○. The above results suggest that simply enriching the steel base with 0 will only unnecessarily increase the sludge production rate and will not be a means of improving the dissolution characteristics of copper cladding anodes. . As explained above, the advantages obtained by using an anode treated according to the present invention are summarized as follows. {The so-called "impurity" in the a'Cu-0 binary alloy anode is only oxygen. Therefore, there is no fear that impurities will accumulate and contaminate the copper glazing bath due to melting of the anode, and a reduction in maintenance and inspection costs can be expected. 'b' By setting the oxygen enrichment amount to at least about 0.1 wt% and simply applying an "activation treatment" to this, the dissolution activity increases significantly, and at the same time, the amount of sludge generated drops to below 1%. . especially

When [0]=0.4 to 0.5 wt%, the amount of sludge generated is 0.07% or less, which is almost negligible.
{c) Not only does the dissolution activity increase significantly, but also virtually no slime layer is formed on the anode dissolution surface, unlike currently commercially available phosphor-containing steel type anodes.
Economic benefits such as a considerable reduction in cell voltage during plating operations can also be expected. [d) Because the amount of sludge produced is low, sludge particles such as Cuo and C Buddha ○ are suspended in the plating bath and adhere to the surface of the object to be plated (cathode), resulting in a rough and defective plating finish. Similar problems are essentially solved.

[Brief explanation of the drawing]

The drawing is a graph showing the relationship between the sludge generation rate and the amount of oxygen contained in the sludge in connection with Examples.

Claims (1)

[Claims] In a method for manufacturing a copper anode material used in a copper sulfate plating solution, the copper anode material contains 0.1% by weight or more of oxygen, and the oxygen-containing copper anode material is heated to 800°C.
A method for producing an anode material for copper plating, characterized by performing a slow cooling treatment from the above temperature at a cooling rate slower than 270° C./hour.