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Organic Solderability Preservative
Organic solderability preservative or OSP is a method for coating of printed circuit boards. It uses a water-based organic compound that selectively bonds to copper and protects the copper until soldering. Compared to the traditional HASL process, the OSP process is widely used in the electronics manufacturing industry because it does not require high-temperature treatment and significantly reduces the risk of metal corrosion, environmental impact and damage to electronic components. The basic principle of SP to form a protective layer against oxidation and corrosion by applying a layer consisting of a mixture of organic acids and nitrogen compounds, etc. The OSP process involves delicate steps designed to ensure the uniformity and quality of the protective layer. Although environmentally friendly and suitable for microelectronic manufacturing, the complexity of the process requires strict control of the composition and quality of the coating agent to guarantee consistent board pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coating
A coating is a covering that is applied to the surface of an object, or substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. powder coatings. Paints and lacquers are coatings that mostly have dual uses, which are protecting the substrate and being decorative, although some artists paints are only for decoration, and the paint on large industrial pipes is for identification (e.g. blue for process water, red for fire-fighting control) in addition to preventing corrosion. Along with corrosion resistance, functional coatings may also be applied to change the surface properties of the substrate, such as adhesion, wettability, or wear resistance.Howarth G.A "Synthesis of a legislation compliant corrosion protection coating system based on urethane, oxazolidine and waterborne epoxy technology" Master of Science Thesis April 1997 Imperial College London In other cases the coating adds a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of organic heterocyclic chemistry focuses especially on organic unsaturated derivatives, and the preponderance of work and applications involves unstrained organic 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of organic heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflow Soldering
Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux (metallurgy), flux) is used to temporarily attach anywhere from one to thousands of tiny electrical components to their contact pads, after which the entire assembly is subjected to controlled heat. The solder paste reflows in a molten state, creating permanent solder joints. Heating may be accomplished by passing the assembly through a reflow oven, under an Infrared heater, infrared lamp, or (mainly for prototyping) by soldering individual joints with a hot air pencil. Reflow soldering with long industrial convection ovens is the preferred method of soldering surface mount technology (SMT) components to a printed circuit board (PCB). Each segment of the oven has a regulated temperature, according to the specific thermal requirements of each assembly. Reflow ovens meant specifically for the soldering of surface mount components may also be used for Through-hole technology, throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immersion Tin Plating
Immersion may refer to: The arts * "Immersion", a 2012 story by Aliette de Bodard * ''Immersion'', a French comic book series by Léo Quievreux * ''Immersion'' (album), the third album by Australian group Pendulum * ''Immersion'' (film), a 2021 Chilean thriller film * ''Immersion'', a 2023 Japanese film directed by Takashi Shimizu * ''Immersion'' (series), a webseries which test the concepts of video games in real life, created by Rooster Teeth Productions * Immersion journalism, a style of journalism Science and technology * Immersion lithography or immersion microscopy, optical techniques in which liquid is between the objective and image plane in order to raise numerical aperture * Immersion (mathematics), a smooth map whose differential is everywhere injective, related to the mathematical concept of an embedding * Immersion (virtual reality), the perception of being physically present in a non-physical world, created by using VR Other uses * Immersion baptism, a type of ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immersion Silver Plating
Immersion silver plating (or IAg plating) is a surface plating process that creates a thin layer of silver over copper objects. It consists in dipping the object briefly into a solution containing silver ions. Immersion silver plating is used by the electronics industry in manufacture of printed circuit boards (PCBs), to protect copper conductors from oxidation and improve solderability. Advantages and disadvantages Immersion silver coatings have excellent surface planarity, compared to more traditional coating processes such as hot air solder leveling (HASL). They also have low losses in high-frequency applications due to the skin effect. On the other hand, silver coatings will degrade over time due to oxidation or air contaminants such as sulfur compounds and chlorine. A problem peculiar to silver coatings is the formation of silver whiskers under electric fields, which may short out components. Specifications IPC Standard: IPC-4553 See also * Electroless nickel immersion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Air Solder Leveling
HASL or HAL (for hot air (solder) leveling) is a type of finish used on printed circuit boards (PCBs). The PCB is typically dipped into a bath of molten solder so that all exposed copper surfaces are covered by solder. Excess solder is removed by passing the PCB between hot air knives. HASL can be applied with or without lead (Pb), but only lead-free HASL is RoHS compliant. Advantages of HASL * Excellent wetting during component soldering. * Avoids copper corrosion. Disadvantages of HASL * Low planarity on vertical levelers may make this surface finish unsuitable for use with fine pitch components. Improved planarity can be achieved using a horizontal leveler. * High thermal stress during the process may introduce defects into PCB. See also * Electroless Nickel Immersion Gold (ENIG) * Immersion Silver (IAg) * Organic Solderability Preservative (OSP) * Reflow soldering * Wave soldering Wave soldering is a bulk soldering process used in printed circuit board manu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroless Nickel Immersion Gold
Electroless nickel immersion gold (ENIG or ENi/IAu), also known as immersion gold (Au), chemical Ni/Au or soft gold, is a metal plating process used in the manufacture of printed circuit boards (PCBs), to avoid oxidation and improve the solderability of copper contacts and plated through-holes. It consists of an electroless nickel plating, covered with a thin layer of gold, which protects the nickel from oxidation. The gold is typically applied by quick immersion in a solution containing gold salts such as gold sulfites with an example being Na3Au(SO3)2 or potassium gold cyanide (KAu(CN)2), with a complexing agent and a stabilizer. The bath needs to be replaced after a certain number of uses and the composition of the gold bath may be patented. Some of the nickel is oxidized to while the gold is reduced to metallic state. A variant of this process adds a thin layer of electroless palladium over the nickel, a process known by the acronym ENEPIG. ENIG can be applied before or aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometer
330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling Despite the various list of dialects of English, English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variati ...), is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) or one thousand million (long scale) of a metre, meter (0.000000001 m) and to 1000 picometres. One nanometre can be expressed in scientific notation as 1 × 10−9 m and as m. History The nanometre was formerly known as the "''millimicrometre''" – or, more commonly, the "''millimicron''" for short – since it is of a micrometre, micrometer. It was often de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Complex
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing chemical compound, compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A Ligand#Polydentate and polyhapto ligand motifs and nomenclature, polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Bond
In coordination chemistry, a coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom. The bonding of metal ions to ligands involves this kind of interaction. This type of interaction is central to Lewis acid–base theory. Coordinate bonds are commonly found in coordination compounds. __TOC__ Examples Coordinate covalent bonding is ubiquitous. In all metal aquo-complexes (H2O)''n'''m''+, the bonding between water and the metal cation is described as a coordinate covalent bond. Metal-ligand interactions in most organometallic compounds and most coordination compounds are described similarly. The term ''dipolar bond'' is used in organic chemistry for compounds such as amine oxides for which the electronic structure can be described in terms of the basic amine donating two electrons to an oxygen atom. : → O The arrow → indicates that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board
A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes and other features (similar to wires on a flat surface) Chemical milling, etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive substrate. PCBs are used to connect or Electrical wiring, "wire" Electronic component, components to one another in an electronic circuit. Electrical components may be fixed to conductive pads on the outer layers, generally by soldering, which both electrically connects and mechanically fastens the components to the board. Another manufacturing process adds Via (electronics), vias, metal-lined drilled holes that enable electrical interconnections between conductive layers, to boards with more than a single side. Printed circuit boards are used in nearly all e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adsorb
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a fluid (the ''absorbate'') is dissolved by or permeates a liquid or solid (the ''absorbent''). While adsorption does often precede absorption, which involves the transfer of the absorbate into the volume of the absorbent material, alternatively, adsorption is distinctly a surface phenomenon, wherein the adsorbate does not penetrate through the material surface and into the bulk of the adsorbent. The term '' sorption'' encompasses both adsorption and absorption, and ''desorption'' is the reverse of sorption. Like surface tension, adsorption is a consequence of surface energy. In a bulk material, all the bonding requirements (be they ionic, covalent or metallic) of the constituent atoms of the material are fulfilled by other atoms i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
