Pure tin and its main problems. Tin plague
Are you interested in pure tin, and the problems that arise with it? from the supplier company AvecGlob? Here you will find the necessary information on this topic.
Pewter tendrils
Tin whiskers are filamentary crystals that are formed on the surface during the smelting of chemically pure tin.
The exact cause of the appearance of tin antennae is still unclear, but recent studies have shown that the presence of nickel in the alloy (even at the impurity level) has a significant effect on the likely growth of whiskers. This is facilitated by the compressive stresses that arise around the formation of intermetallic compounds. Reducing the external voltage can be minimized by changing the design of the part, which requires tin to manufacture.
Further, the main measures aimed at preventing the growth of whiskers are considered.
Methods for preventing filament formation
Storage — parts should be stored in dry, temperature-controlled rooms;
Surface treatment before soldering — sudden and rapid changes in temperature should be avoided. This reduces the risk of the formation of compressive stresses in the metal, which arise from the discrepancy between the coefficient of thermal expansion of the base alloy and the coating materials.
Supplier — AvekGlob Company — offers various types of products from tin of domestic and foreign production, which meets the requirements of standards. The products are offered at affordable prices from the manufacturer. The supplier guarantees the timely delivery of products to any address specified by the consumer.
Defect detection
The growth of tin crystals is associated with the formation of substrates. The problem involves changing the color and color of the alloy. The coloring is caused by the formation of an oxide on the surface of the coating. Despite the considerable visual effect, this usually does not worsen the soldering process. However, when coating the coating, the change in the color of the alloy is more significant and can lead to a deterioration in the quality of the soldered joint. There are steps that can be taken to minimize these cases.
Ways to prevent
Specification of the coating when applying a thin layer of tin on steel surfaces (connectors, food containers).
Preheating the solder — heating should be applied at a gradual rate of no more than 1 ° C / s from the ambient air. If possible, the parts should be stored at a preheating temperature for a short period of time so that all components and laminates can equalize at the same temperature.
Soldering temperature — for ideal conditions, soldering should be carried out at a temperature of 240 ° C ± 5 ° C.
Regardless of the furnace temperature, the temperature of the component should be checked with a probe that measures the temperature on the surface of the printed circuit board. The exposure time to the highest soldering temperatures should be kept to a minimum, which will ensure a good soldering connection.
Convection ovens provide the maximum control of temperature gradients and stable temperatures. Infrared ovens are not recommended — the control process is difficult, and the surface temperature can vary by 40 ° C.
The color change is associated with the formation of tin oxide, which is formed in the presence of oxygen and is usually a blue reflective surface effect. This effect at temperatures above 300 ° C can be avoided by soldering under pure nitrogen.
Supplier — AvekGlob Company — offers to purchase tin in a wide range of profiles and technological applications. Products can be bought at a price formed on the basis of European and world standards. Implementation is possible in bulk and retail, for regular customers, a flexible system of discounts operates.