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Донской Государственный Технический Университет
Кафедра: “Машины и Автоматизация Сварочного Производства”
«Особенности пайки неметаллических материалов и ферритов»
Выполнил студент группы
Проверил
г. Ростов-на-Дону
2003 г.
Contents/ Содержание
I Introduction 3
II Soldering of semiconductors 4
III Soldering of graphite 7
The soldering of graphite with steels 9
The soldering of graphite with copper 11
The soldering of graphite with graphite 12
IV The soldering of glasses with metals 13
I Введение 17
II Пайка полупроводников 18
III Пайка графита 21
Пайка графита со сталями 23
Пайка графита с медью 24
Пайка графита с графитом 25
IV Пайка стекла и металлов 26
I Introduction
In the given work features of the soldering of metals with nonmetallic materials, namely the soldering of semiconductors, the soldering of graphite with metals are considered, the soldering flew down with metals.
The soldering of semiconductors use as at internal installation of devices - the soldering current supply, the soldering of transition on crystal owner, and at external installation - the soldering of external conclusions, hermetic sealing.
Connection of graphite with metals is caused by economic reasons, and also necessity of realization of positive properties of graphite. Examples of such designs are lengthy heaters, crucibles and pumps for smelting of metals, electrodes of arc furnaces, large-sized anodes of mercury rectifiers, heaters of mine furnaces, high-temperature heat exchanger, heater elements, etc.
The soldering of metal with glass apply at creation of a different sort of vacuum devices (floodgates, observation ports, etc.), at manufacturing lamps (from tiny up to powerful generating), in manufacture of large mirrors of optical devices, for facing an internal part of pipes of oil pipelines, etc.
The fused glasses well moisten all metals under condition of presence on their surface of an adsorbing layer of oxide and heating to the corresponding temperature. Formation of strong connection between metal and glass depends on pressure in a zone of junction, presence of gas bubbles, process electrolysis and расстекловывания glasses.
II Soldering of semiconductors
A surface of a product from the semiconductor, subject to the soldering, preliminary cover by tin in melt solder with the help of a ultrasonic soldering iron, way of a galvanic covering (nickel plating, gilding).
The soldering make in furnaces with a controllable atmosphere (neutral, regenerative), in vacuum or a method of resistance preliminary covered by tin surfaces. At connection of products with available transition it is required to maintain strictly temperature of heating to what apply temperature regulators.
The soldering of thin electric conclusions can be carried out on air microsoldering irons with use of protective or active gumboil (alcohol a solution of rosin, a gumboil on the basis of chloride ammonium). After the gumboil soldering a product wash out deionized water and dry.
In manufacture of semiconductors of operation on assembly of a product under the soldering carry out in the assembly rulers having a controllable atmosphere and consisting of several survival suits connected among themselves in which air or nitrogen of the certain temperature and humidity moves.
At the soldering of semi-conductor materials solders should form electro-hole transition or not straightening ohmic contact. In manufacture germanium and silicon devices as a basis apply aluminium, indium and alloys on the basis of tin and lead. For creation in a place of contact of conductivity of electronic type in a basis of solders as impurity enter phosphorus, arsenic, antimony and bismuth. For maintenance of not straightening ohmic contact in a basis of solders add a bor and gallium.
At creation of transitions and ohmic contacts on intermetallic connections apply tin, bismuth, antimony, zinc, cadmium, etc.
Structures of solders and modes of the soldering germanium and silicon are resulted in tab. 1. To the soldering of semiconductors apply also solders - pastes on the basis of gallium. For maintenance of reliability of wetting of a contact surface use ultrasound.
Table 1
Compositions of the solders and modes of the soldering germanium and silicon
Soldered material Composition solder (mass shares), % Modes of the soldering Using, particularities of the process
Temperature, С
Time, mines.
Ambience
Silicon n-type Pb – 63;
Sn – 35,5;
Sb – 1,5
720÷730
12÷13
Gumboil
Pb – 97;
Sb – 1,5;
Ni – 1,5
Aluminum
___
___
Vacuum 6*10-2 Pa
Silicon valves
Silumin
Ag – 97;
Pb – 2; Sb - 1
Silicon Gold (contact-reactive soldering)
420
___
___
Integral schemes
Arsenide gallium + +nickel and silicon + +nickel
Ga – 39,6;
Sn – 4,4;
Cu (powder) -56
100
Heating by ray of the lazer
Silicon KEF + ковар 29НК
Glass S48 - 1 or "Pireks"
980
10
Argon Soldering in two stages:
1) glass with коваром;
2)glass-коваровый node with silicon U = 800÷1000В
400÷450
20÷25
Germanium + platinum Sn – 99; Bi - 1 280 5 Hydrogen ___
The structure of solders influences electric parameters soldering devices, therefore at a choice of solders it is necessary to take into account their physical properties, for example conduction, temperature factor of linear expansion.
Structure of the solders used for low-temperature of the soldering of semiconductors, are resulted in tab. 2.
Table 2
Compositions низкотемпературных solders applicable when soldering germanium and silicon
Contents (mass shares), % Тmelt, °С
Bi Pb Sn Cd
50,1
52,0
56,0
- 24,9
40,0
44,0
36,0 14,2
-
-
64,0 10,8
8,0
-
- 65,5
91,5
125,0
181,0
As gumboil use alcohol and water solutions of chloride zinc and chloride ammonium or vaseline pastes (no-acid gumboils - a solution of rosin in alcohol). At the high-temperature soldering apply gumboils on a basis drills.
Diffusion processes between solder and the semiconductor promote formation of the connections increasing transitive resistance of a thermoelement, therefore time of contact of the semiconductor with solder in process covering by tin and the soldering should be extremely limited. The deviation of temperature of heating at the soldering should not exceed 2-3 °С.
III Soldering of graphite
The small density of graphite, the high heat conductivity close to heat conductivity of metals, and also higher thermostability, than at the majority of ceramic materials, have caused its application in various branches of technics. With rise in temperature up to 2000÷2500 °С durability of graphite grows; at these temperatures it has the greatest strength from all known materials.
Use of the graphite and combined designs is defined by way of their connection. Mechanical fastening, pasting, welding and the soldering is known. The soldering is the most technological and economic method of connection of the graphite materials, providing reception of high-strength, electrowire and tight connections.
Physicomechanical properties of graphite depend on a kind of initial raw material and parameters of technological process of its reception.
The capillary, contact-reactive, diffusion soldering and soldering-welding can be applied to connection of graphite.
Graphite is well moistened with refractory metals (the titan, zirconium, silicon, hafnium, vanadium, niobium, tungsten, molybdenum), metals of group of iron, aluminium, and also silicon and a bor.
The basic stage of process of the soldering of graphite with metals is its impregnation by the fused solder. The metal skeleton formed at it determines durability soldering connections.
Difficulty of connection of graphite
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