Surfactants are widely used in textile, pharmaceutical, cosmetics, food, shipbuilding, construction, mining, petrochemical and civil washing and other fields.It also has certain application in metal surface treatment.According to the structure and physicochemical properties of surfactants, especially some non-ionic surfactants, we have applied it to the fine polishing technology of small hard metals or alloys, and achieved obvious results.In the process of metal parts finishing, polishing is a commonly used technique, in the conventional mechanical polishing method, no matter use polish rods, polishing paste or polishing liquid abrasive ingredients commonly, such as kieselguhr, sintering or sintered alumina, iron lead powder, etc., are related to the chemical polishing agent and electrochemical polishing agent have been reported, but for the application in the semiconductor device of tungsten manganese ( 1×1.5mm), as well as in electronics, light industry, textile and other industries used in a variety of smaller metal (especially hard alloy) parts, the requirements of fine polishing to achieve a lower roughness, the use of the above polishing technology is difficult to meet the requirements.For this reason, we have developed a liquid polishing agent for finishing tungsten and various cemented carbide parts.And get better efficiency in practical application.

  1, polishing agent formula

  The components of the solution

  The above components are mutually dissolved in a fixed proportion to form a multi-component mixture.

  Physical and chemical properties of polishes

  Polish is pale yellow viscous liquid viscosity: 44.5 s / 25 ℃ (tu 4 cups), pH: 9, density: 1.01 g/cm3 (20 ℃).Good water solubility, good stability for different water quality, and no precipitation generation.It has obvious thickening effect on water, and shows slight emulsification when diluted with a large amount of water.Non corrosive, stable in acid and alkali conditions.

  The role of the components

  RCON(R 'OH)2: The fatty alcohol-amide compound is a non-ionic surfactant, soluble in water, has obvious thickening effect on water, and has excellent foam stability.From the point of view of its molecular structure, it has an amide bond, which should have a large polarity, and there are alcohol carboxyl groups in the molecule, so it should have a strong affinity with metal materials, R-group is a longer hydrocarbon group, through the length of the chain can adjust the size of its water solubility, it determines the dilution of water.R(OCH2CH2)nOH: Alkyl phenol polyoxyethylene ether compounds, for another class of non-ionic surfactants.It has good chemical stability and surface activity.The size of the n value of the application of choice, when the N value reached a certain value is water-soluble, has a good cleaning ability, compared with ionic surfactants, it on acid and alkali and hard water stability is better.ROH: We add a certain amount of secondary alcohols to the mix.Its purpose has two: one is to adjust the viscosity of the solution, and the other is that it has a certain defoaming effect, which can prevent excessive foam in the polishing process.Antirust agent and corrosion inhibitor: a small amount of these two substances are mainly used to protect the metal surface, to prevent corrosion in storage and application process.

  Discussion on polishing mechanism

  In this paper, the mechanism of finishing polishing of tungsten column by liquid polishing agent is discussed, and the mechanism of finishing polishing of other cemented carbide parts is basically the same.The specific operating conditions are: fill a certain number of small metal tungsten column (1×1.5mm) in a hexagonal drum (the speed is 55г/min), add the polishing agent 500ml, then add water 6000ml, in the drum for polishing.The previous process was a rolling polish in 600# gold steel sand and water.

  The rolling finish of tungsten column in gold steel sand belongs to rough finish.Under these conditions, the edge and corner burrs and the fine surface of the tungsten column can only be polished preliminarily. In fact, the metal tungsten column roughed by gold steel grit has not achieved the polishing effect, and its surface is dark and gray, which is due to the wear marks left on the surface during the polishing process.The use of this liquid polish is the next step in the finishing operation of metal fabrication, resulting in extremely low roughness.The polishing mechanism should be the double result of the friction between a certain number of metal tungsten columns in the rotating drum and the viscous friction of the polishing fluid on the fixed surface.Therefore, in the polishing operation, polishing agent plays two roles, one is to rely on its large affinity to the metal tungsten column and form a protective film on the surface to buffer due to the rotation of the roller, metal tungsten column phase to the impact of friction, so that it no longer produce large scratches.On the other hand, it plays a sticky role.That is, the metal tungsten column as the surface of the protective film is not invariable, but in the movement of dynamic balance, the sliding friction between the viscous liquid and the metal tungsten column surface, this friction is more uniform, more detailed, so it can achieve a lower roughness.

  Non-ionic surfactant as the main component of a new type of liquid polish, because the molecules have a greater affinity and wettability of tungsten metal and other kinds of cemented carbide products.At the same time, it has a certain cleaning and anti-rust effect, so it can be widely used in the fine polishing of various metal parts.The practice shows that the surface of the metal tungsten column polished by the agent is bright and uniform, and the lead welding lines are all qualified. It has been used by a semiconductor company in Tianjin for many years and achieved good benefits.

  Separation of surfactants: by the affinity of different parts of the molecule to the two phases, so that both phases regard it as the components of the phase, the molecules are arranged between the two phases, so that the surface of the two phases is equivalent to the interior of the molecule.Thus reducing the surface tension.Since both phases regard it as a component of the original phase, it is equivalent to that neither phase forms an interface with the surfactant molecule, and it is equivalent to that the interface between the two phases is partially eliminated in this way, thus reducing the surface tension and surface free energy.