SZFitech

 In order to protect human health and safety and to improve the environmental performance of electronic equipment, the European Union adopted the Restriction of Hazardous Substances (RoHS) Directive in 2006, which prohibits the use of certain hazardous substances, including lead, in electronic equipment. However, high-lead solder (i.e., lead-based alloys with more than 85% lead) is not regulated by the directive and can be used in any application. The melting point of high-lead solder is up to 300°C or more, and the commonly used alloys are Sn5Pb92.5Ag2.5 and Sn5Pb95, which are widely used in high-temperature component connection, military manufacturing, medical devices and other specialized fields. These areas require high reliability and stability of the solder, the need for solder to withstand high temperature, high pressure or high frequency working environment, while ensuring the performance and life of the components. High leaded solders are able to meet the nee...

 AEC-Q200 certification for automotive electronic solder pastes is a key standard to ensure that they meet the high reliability requirements of the automotive electronics industry. the AEC-Q200 certification covers a series of stringent test items, the following three dimensions from the core test items, test conditions and requirements, and the significance of the certification is described in detail: I. Core Test Items AEC-Q200 certification for automotive electronics solder paste and other passive components, designed for multi-dimensional test items to simulate the extreme environment of their actual use in the car: Temperature and humidity stress test High Temperature Storage (HTS): 1000 hours at 125°C or higher to verify the long-term stability of solder paste solder joints at high temperatures. Low Temperature Exposure (LTS): Long-term storage at low temperatures (e.g. -40°C) to ensure the low-temperature performance of solder joints. Temperature Cycling (...

 The core steps of the lead-free soldering process are listed below, each of which contains key control points to ensure solder quality: 1. Optimisation of pre-soldering preparation Introducing automatic optical inspection (AOI) equipment for initial inspection of component pins and PCB pads to reduce the time required for manual visual inspection. Use ionic contamination tester to check PCB cleanliness to ensure that it meets the low contamination requirements of the lead-free process. Establish solder paste inventory management system and follow the first-in-first-out (FIFO) principle to avoid waste of solder paste due to expiration. 2. Solder paste printing optimisation Laser nano-coated or electro-cast stencils are used and the opening edges are nano-polished to reduce solder paste residue. Introduced an online stencil thickness detection system to ensure that stencil thickness deviation is controlled within ±2μm. Using a closed-loop control system, real-time monitorin...

 Technical Analysis of Kirkendall Cavities and Ni Oxidation in ENIG Pad Welding I. The formation mechanism and effect of Kirkendall Void (Kirkendall Void) Different atomic diffusion and interfacial reaction rate is different Au dissolution and IMC formation: when soldering, ENIG pads in the Au layer quickly dissolved into the tin-lead solder, and Sn reaction to generate AuSn₄ intermetallic compounds (IMC).At the same time, Sn in the solder reacts with the Ni layer to form Ni3Sn4 IMC. Accompanying of P-rich layer: due to the doping of phosphorus (P) in the Ni layer, P is crowded out near the interface during the growth of Ni3Sn4, forming an amorphous P-rich layer (Ni-P+ layer). Reasons for the formation of voids Ni diffusion and lattice mismatch: Ni atoms diffuse into the solder faster than the reverse diffusion of Sn atoms into the Ni layer, resulting in the formation of an atomic flux imbalance at the interface.This imbalance triggers tiny voids between Ni3Sn4 and th...

Solder paste soldering tin splattering refers to the soldering process, high temperature soldering iron tip contact solder paste, solder paste instantly produce a violent reaction, issued by the explosion sound and splattered small tin beads of the phenomenon. The following are the main reasons for tin splattering and solutions: I. Main causes of tin splattering Material moisture Solder or PCB moisture: solder paste, solder wire or PCB board if not properly preserved, easy to absorb moisture in the air. Soldering, moisture vaporisation at high temperatures, volume expansion leading to tin splattering. Moisture in components: If some components are not sealed, they may absorb moisture and cause tin splattering when soldering. Flux problems Improper dosage: too much or too little flux may affect the quality of soldering, too much may lead to solvent evaporation, residue decomposition gas. Abnormal composition ratio: flux containing volatile substances or active agent r...

 The technical requirements for solder pastes in the aerospace sector reflect the deep integration of cutting-edge materials science and engineering practice.The following is a systematic overview of the technical challenges, solutions and industry trends: I. Technical Challenges and Response Strategies in Extreme Environments Thermodynamic limit breakthrough Phase change control technology: adopt gradient alloy design (e.g. AuSn-AgCu composite solder) to achieve step-by-step thermal stress release through the layered structure of metals with different melting points. Thermal cycling accelerated testing: Development of life prediction model based on Arrhenius equation, combined with more than 1,000 times of cold and thermal shock test (-196℃~250℃) to verify material stability. Mechanical Dynamics Adaptation Microstructure Strengthening Mechanism: By doping silver nanoparticles (50nm), the yield strength of solder joints is increased to 520MPa while maintaining 8%...