In general, the normal gap value of tungsten points of the distributor is between 0.35mm and 0.45mm. If the gap is large than normal gap value of 0.1mm, the petrol consumption of car engine will more than 3% of normal petrol consumption; if smaller than 0.1mm of normal gap value, then the consumption will add 5％of fuel.

The influence factors of the automotive ignition system performance are ignition advance angle, ignition energy and the maximum secondary voltage. If the ignition advance angle is too large or small, the mixture gases would not burn normally after igniting. If the ignition energy is not sufficient, the mixture gases would not properly ignite. If the maximum secondary voltage is low, the spark plugs would not normally flash over. The factors described above will decline the power of engine, rise fuel consumption and dysfunction and other aspects. Therefore, if the gap of tungsten points of distributor is proper, the influence of car ignition advance angle, ignition energy and the maximum secondary voltage to car ignition system will be reduced.


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Tungsten points, also known as tungsten electrical points or tungsten contacts, which are used in equipment, instruments and switching equipment as a contact part. They are playing a role in turning on and turning off the current. Thus, tungsten points will influence the properties of the switching devices directly when they are in running state. People began to use contact materials about a hundred years ago, which started with pure silver, pure gold and pure platinum and other contact materials. People began to use alloy materials until the 1940s, such as, gold silver, platinum indium and silver copper materials. People gradually found composite materials of precious metal after the 1960s. People gradually turn their attention to tungsten materials since tungsten was found in 1781.

Tungsten contact materials possess high purity, high melting point (up to 3422 ° C), high density, high hardness, nice wear resistance, good corrosion resistance, low conductivity and other properties.

Properties of silver material are: silver owns excellent processing performance, the best thermal conductivity and high antioxidant capacity and other properties in all metals.


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Silver tungsten points’ preparation can adopt infiltration or powder metallurgy method.

Silver material properties:
Low wear resistance;
Low melting point;
Low hardness;
Volatile;
Good thermal conductivity;

The silver point is easier to form arcs and weld when its load is large;
Under the influence of DC, silver film form electrical erosion spikes because of silver’s low hardness and volatile characteristics;
Silver will form silver sulfide film in the surface of sulfur or sulfur compounds at the condition of high temperature and humidity,.

The content of tungsten of silver tungsten points is usually around 20% -80%. Silver tungsten points’ merits: arc erosion resistance, excellent electrical wear resistance, good electrical and thermal conductivity, good oxidation resistance and good anti-welding capability. Silver tungsten points’ defects: unstable contact resistance. Tungsten will produce mixed oxide when the silver tungsten points operating frequently and the splash degree of contact resistance of the film surface will improved.

Silver tungsten points’ application: widely applied in micro-switches, circuit breakers, thermostats, etc., and can also be used as a part in high current heavy equipment and electrical points.


Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
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Tunable dye laser spectroscopy has been used to study energy transfer processes in CaWO₃:Sm³⁺ crystals. Fluorescence and excitation transitions for samarium ions in different crystal-field sites have been identified and their changes in width and position with temperature studied. This information is used to characterize energy migration among samarium ions as a function of temperature, samarium concentration, time after the laser pulse, and pressure. The interaction mechanism causing energy migration is identified as electric quadrupole-quadrupole. At low temperatures it was found that only single-step transfer between nearby ions takes place, while at high temperatures multi-step diffusion of energy occurs. These results are interpreted in terms of the Anderson (1958) localization concepts for systems with inhomogeneously broadened transitions, and quantitative estimates of the transfer rates and diffusion parameters are obtained.

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