|1.Theory of metal corrosion and its prevention|
|2.Discoloring causes of copper wire|
|3.Discoloring preventatives of copper wire|
|1.Theory of metal corrosion and its prevention|
Metal corrosion occurs in phase between metal and its surroundings.
The causes of metal corrosion cannot be specified because of their uncertainty factors which depend on the intensity of electronic donating and accepting (standard electrode potential) in specific metal itself.
Existence of unstable factors such as dislocation (spiral, edged), dislocation causesE cavitiesEstepsEimpuritiesEpitsEkinksElattice defects, etc.
Metal surface energy is unstable from potential point of view and the potential tends to neutralize. The metal surface reacts adsorptive to atmosphere, water, ionized Inorganic salts and organic compound, and obtains stability. However, the surface is the most problematic place in corrosion matter.
Generally speaking, wire drawing oil is meant for lubrication effects in metal process.
The oil contains a lot of adsorptive reacting materials (ionized). The materials react to metal surface and produce corrosion causing materials. In case of mal-lubrication oil, metal surface and sustains hard damage and quantity of oil film is going to increase.
And corrosion becomes serious. Therefore, giving priority in lubrication effect and minimizing damages leads to prevent corrosion. (Nonionic oils without ionic activity create the@most dangerous situation for corrosion in addition to low lubricate effect.)
Rust preventatives act as neutralization agents and stabilizing (changing into non-conductor) with their inorganic and organic substance.
|As corrosion occurs in the metal gunstable (caprice) phenomenonh.
Its prevention methods depend on metal engineering and Electrochemical ones.
|2. Discoloring causes of copper wire|
Discoloring occurs in one side surface or whole surface by corrosion gasses, acid alkali atmosphere in electric plating process, chlorine gas produced in flex of tin plating, chlorine gas emitted in vinyl chloride covering process, automobile exhausts, etc.
Spray of beginning rain mist
Various discoloring cause materials dissolved from atmosphere make spots or whole Discoloring occurs) makes inside discoloring.
Moisture in room
- Moisture from lubricant, especially moisture in rainy season.
Moisture from lubricant, especially moisture in rainy season.
Water rolled into coil bobbin (especially in containing copper ions case, large Discoloring occurs) makes inside discoloring.
Wire drawing oil
a)Accumulation of waste materials: Spot discoloring in storing
b)Decline pH: Discoloring homogeneously
c)Increase of copper ions in lubricant: Discoloring homogeneously
d)Component of wire drawing oil (especially high ratio of active agent): discoloring homogeneously
e)Bacteria (in case of acidic bacteria): Discoloring homogeneously
f)Water contents (heavy metals make cores for corrosion): Discoloring homogeneously
Storing condition of drawn wire
In case of storing on concrete floor discolor occurs in spotted share, so-called perched sesame with salt shape, by attaching of soil lime powder. No discoloring wire can be seen in 3,4 layers of under side of coin bobbin.
Spray of wire drawing lubricant
When sprays of wire drawing oil from finishing dice falls on finished wire, babbles of the oil burst and make circle or dotted discoloring. To prevent those discoloring keep the spray add finished wire or cover the wire vinyl sheets, etc
Mishandling and flaws of annealing
Problems in cooling water (well water, industrial water, others, remaining salts) Insufficient draying in annealing
Hysterics of factory site
After windy weather, a lot of radish dots are seen. Result of investigation of the discoloring parts shows the parts containing iron element. The site had been tea farm and power of iron (iron oxide) had been scattered as acid soil improvement agents. It has been known that the iron element creates another discoloring phenomenon. For prevention, to step iron-containing sands scattering surround has succeeded Anti-discoloring effects.
Close to seashore or being carried by typhoon salinity
(Injury from salt)
Existence of extraordinary smog in neighborhood displays hazardous factors or not.
|3.Discoloring preventatives of copper wire|
When copper material is dried, oxidation membrane is not formed. Only protective cuprous oxide membrane foamed 10 ` 50đ thickness and reaches balance. Therefore, the@Copper material looks like no discoloring state. However, existence of water, organic Inorganic substances on the surface of copper material and changing surrounding atmosphere will oxidate or dissolve the surface in accordance with the protective cuprous oxide membranefs electrical and chemical unstable situation. And the oxidation will make the cuprous oxide membrane change into cupric oxide membrane and then discoloring will be seen.
Corrosion of copper wire is mainly classified two patterns, one is wet atmosphere corrosion related water and the other is dry atmosphere corrosion. Discoloring depends on various conditions of these two patterns respectively.
As these discoloring are not only bad out looking but also give various harmful influences such as poor annealing, poor jointing, poor membrane, etc., preventive measure should be taken for them.
Basically counter measurements are considered as follows, @ : Improvement atmosphere A : Formation of protective membrane B : Metallurgical improvement, independently or fixedly.
From @ viewpoint: first of all, air-conditioning of storing place, temperature, humidity, and pH, dew condition, protection from touching materials.
From A viewpoints: using discoloring preventatives
From B viewpoints: to make alloy with SnE ZnE NiE CrE etc. Excepting special cases, these kinds of alloys are seldom used for electric wire.
Discoloring preventatives consist of gas, liquid, solid (organic matters, inorganic matters metals) anyone of them protects drum oxygen and water, which are typical discoloring cause materials, and also inhibits from occurring local cell.
Discoloring preventatives also consist of adsorption type and adsorption with chemical reaction type. Although either type can be resolved in water or solvents, once after formation of membrane by chemical reaction and adsorption, no resolving character of membrane into water or solvents is importantly required
As convenient materials for these specific characters, we can find surfactants. The effect of discoloring depends on the structure of surfactants.
On the other hand, in some cases, membrane has to be removed immediately after performed discoloring prevention by discoloring preventatives of membrane forming type for the sake to obtain conductivity. Therefore some removable character should be considered.
(In case of no removing, adaptability with later part processing also should be considered) in using discoloring preventatives, selection of using methods and using conditions is also required.
|In wire drawing process, every step of processing is in the situation of being pequired discoloring preventatives.|
Required discoloring preventing treatment is prevailing in whole process, such as discoloring prevention of rollingEdiscoloring prevention after drawing wireEdiscoloring prevention at electric annealingEdiscoloring prevention after middle size wire drawingEdiscoloring prevention after pot annealingEdiscoloring prevention after small size wire drawingEdiscoloring prevention after coating processEdiscoloring prevention for transportationEdiscoloring prevention for finished wire, etc.
From these processingfs, we will explain the relation of our companyfs products and discoloring preventativesf required characters, one by one
|From these processingfs, we will explain the relation of our companyfs products and discoloring preventativesfrequired characters, one by one.|
|Discoloring prevention at electric annealing|
For this process, discoloring prevention, 0.2`1.0% additives for cooling water will protects membrane on wire surface annealing, and the membrane keeps acid adequately. Any type of cationic, anionic, nonionic, fits for this process, but as mix using of different type ion altogether invites declining effect occasionally. Users have to pay attention to the point. All these discoloring preventatives resolved or disperse stably in water, and formed membrane woks effectively as surface treating membrane for plating, jointing and after coating treatment.
[PRODUCTS] : M-19EM-20EJ-9EJ-20E500-WE500-WAE500-WDE500-WEE500-WXBE396
|Discoloring preventatives for hard copper wire|
gAfter ward paintingh on copper materials after drawing wire, will protect copper surface from discoloring during storing. Discoloring preventing is treated in normal temperature and occasionally wiper blowing of water is required. Some discoloring preventatives of this type resolve in water and fit with cationic type and nonionic type.
In case id using discoloring preventatives for hard copper wire, the agents have to be used in higher density than the density of using in electric annealing.
On the other hand, for about finish wire materials, solvent resolving type agents are often used.
[PRODUCTS] : 500-OGE500-PX1
|Discoloring preventatives at cross-linked polymer coating|
In almost all cases, Non-water types of discoloring preventatives are used. However, in case if using water type agents, removing water process is defiantly required.
Benzotoriazol covers copper surface as net shape by linier polymers and is tolerable at high temperature of 200 and has ability to amend broken membrane, being used extremely wide sphere for copper materials.
[PRODUCTS] : 500-PX1
|Discoloring preventatives at pot annealing|
Discoloring preventatives in severe@environment of over 250 cannot be found at present. But, in the sphere of not extending over 350 , coating by co-using of high melting point polymers with triazol and toriazol additives is considered effective.
For about over 350 , the method of raising purity of inert gas oxygen absorbing column is able to encounter.
|Discoloring preventives in case of acid room atmosphere|
In the environment of using flux, or under the influence of acid substances, discoloring preventatives of outstandingly good adaptability of cation type become stable in acid.
Cationic agents are the most suitable ones for this case. And a nonionic discoloring preventative is the next to cationic ones in efficiency.
[PRODUCTS] : C-19E500-WAE500-WDE500-WXB
|Discoloring preventatives under high humidity conditions|
In rainy season or fall rain season, cationic or anionic discoloring preventatives are useful. Especially, cationic ones form stable hydrophobic membrane on conducting surface. The membrane remains as effective film in dew condition.
[PRODUCTS] : 500-WE500-WAE500-WDE500-WEE500-WXB
|Discoloring preventatives in case of deterioration of drawing oils|
After long time using of drawing wire oils, deterioration of the oil contents is going to progress, among surfactant agents, especially nonionic emulsifiers wick decompose and yield hydroscopic by-products, which may give influence to thickness of water membrane on conducting surface. For about the type containing higher ratio surfactants among drawing wire oils, these attentions should be paid without this process, from beginning.
And by mixing iron contents or increasing various inonic contents, discoloring condition Is getting worse naturally. In these cases, if soap content is existing, the soap content will form membrane, which blocks water layer, but over exhaustion of soap content invites soluble drivers from water layer and ions. In these cases, discoloring can be seen, before discoloring prevention treatment has been done in later process.
Discoloring preventatives are no effect to reduce formed acid membrane. Therefore, Discoloring preventatives must be put into drawing wire oils step.
As almost all drawing wire oils consist of anionic agents, discoloring preventatives of caution type should not be added. Adding small amount of discoloring preventatives of anionic or nonionic types, or pouring soap can reduce discoloring. And, every one-month, replacement of drawing wire agents is recommended.
[PRODUCTS] : 101EKEM-1E 900-UXE 2600-UXE 396
|De-scaling after discoloring|
After above-mentioned treatments, black acid discoloring can be removed by, for example, Adding reducing agents into cooling water of conduct annealing. Acid membrane (black color) near by surface can be reduced and surface of wire can get original color tone back by being passed through the cooling water again.
[PRODUCT] : 108