DE1521910A1 - Process for the production of thin metal layers on an electrically non-conductive material - Google Patents

Description

PHN. 1292

Dipl.-Ing. HORST AUER ^{dJo / MR}

Patent attorney
Applicant: NV PHILIPS 'GLCEiLAMPENFABRIEKEN

File: PHN-1 292
Registration from «" | 3 · 12 · 66

Processor, for the production of thin metal layers on one electrically non-conductive material.

The invention relates to a method for applying thin metal paints. on an electrically non-conductive material. In-übe £ ond »re never refers to eir. Process for the production of a rr.it ιhospherhaltigex nickel coated elek- ι ·; trically conductive material nicr.t \ such as ceramic, glass or plastic, dfi: <ait the Nicicelüberzug as an electrical tfiderstandskörper renutzt weraen kar.n. The invention also relates to a method. Attaching metal layers extremely thin are and have soiiit a high electrical resistance, of the 11 "in CLn per ^ uadrat .mindestens 1 CG, which corresponds to a maximum thickness of 1üO ^p A, and by this method r anget ·.. - ■ r. Te Schienten.

9098A4 / 16A9

BATH ORIGINAL

1b2191U

PHH. 1 292

hat is known to produce resistors by ceramic

mix rods coated with a layer of phosphorus-containing nickel will. It is important that this state is in large numbers can be produced in a highly reproducible manner, the resistance values should only have low tolerances. However, it is extremely difficult to meet these conditions with resistors high Afertes, especially with very thin metal layers coated electrically non-conductive material

fill f. It can increase an existing resistance

¹ C, so the metal layer is locally removed by cutting or etching and for the electrical power supply. a small amount remains, but the maximum resistance values that can be achieved in this way are also not high enough for certain applications, so that the smell of thinner metal layers, which form the subject of the present invention, is thinner.

According to the invention, a method is used, dia from thin nickel layers on non-conductive material, e.g. ceramic, Glass or plastic, which metal layers made of phosphorus Nickel exist and by "electroless nickel plating" (in the 2C English literature called "electroless nickel plating") according to publication 265 in "The American Society of Testing Materials" are attached, these layers being exposed to a

co exposed to the metal solvent, let dissolving # ir-

tf> kung decreases after a certain time, so that the solution speed

* ^ 25 speed star * is reduced. After an initial period, the. Ge

_ »When the wind is off, the loosening decreases strongly, so that the loosening takes a very long time

* - sair. takes place and a settable point in time is reached

the influence of the chemical substances which dissolve the layer

BATH ORIGINAL

PHH. 1292

can be terminated, so that the ao treated objects have resistance values «it very low tolerances.

Sas electroless nickel plating consists of the reduction of an in Lasser dissolved Kickelsalzes, whereby metal is on with this!? Solution covered objects deposited after the objects thoroughly cleaned, sensitized and then activated by one of the known methods, which are also described in the aforementioned publication in A.3.T.M. can be specified. The objects can e.g. by wetting them with a solution of a tin sslzes sensitized and by wetting with a solution of a Pelladiuasalzes are activated. As a result of these treatments, the object is covered in a solution with a nickel salt and a «reducing agent with a layer containing phosphorus Mickels when the reducing agent consists of hypophosphite ions fce consists. When this layer has formed, after According to the invention, the objects treated in this way are treated in a bath which dissolves the hickle layer. This bath can be made of water or • Iner wfiseeric-en solution of an acid exist with air passing through the bathroom is headed. Suitable acids are e.g. sulfuric acid, Hydrochloric acid, phosphoric acid. The layer phoschorhaltien Kinkel dissolves «so that the resistance inda value always increases while the decrease in layer thickness is very much. <jleichmäsai # is going on. lecn the layer is dissolved at constant speed

_o and cie thickness of the layer jro ώβΐteir.heit would decrease a constant

CO 25 «rfänrt, the * idc resistance continues to increase. The resistance

♦ * value would soon become infinite or almost infinite. Ea "- * shows, however, that after some time the speed of movement dee

J ₀ LcOer.s strongly minimizes, so that the Aiierstanddwert only long-

sai, Zuniaxt. is fet nioiii clear which Grui, i vorliert to it; perhaps

BATH ORIGINAL

PHN. 1292

a passive layer does not form on the nickel phosphorus. For clarification, a curve 1 is given in the drawing, in which the duration of the action of the liquid dissolving nickel-phosphorus as the abscissa and the logarithm of the resistance in ohms per as the ordinate. _t uadrateinheit is applied. It can be seen that the resistance value initially increases relatively quickly, while this increase is braked after 20 to 30 minutes, whereupon the curve turns horizontally and runs more horizontally, but without becoming completely horizontal.

For comparison, curves 2 and 3 show the course of the resistance value if this slackening does not occur; these curves have a course that is always closer to the vertical.

The invention is explained in more detail by means of the following examples. . ♦

Example I.

Ceramic rods made of low-alkali porcelain are after degreasing, Sensitize and activate with a layer of phosphor containing nickel coated. The layer thickness of the nickel is changed in such a way that the resistance of the rods is 9 ohms per square and. that of rods II affects 15 ohms per square.

The electrical resistance of this 3t * be per surface layer is increased by a one-hour treatment with a solution of 1N sulfuric acid, through which solution - air is passed. As a result, the resistance value of Ue> berzu / p increases with bars I up to % C ohms per square and with bars II bia to 11,000 ohms per square.

909844/1649

""" ORIGINAL

PHN. 1 292

By the method described in Befepiel I, a stick is made with coated with a layer of phosphorus-containing nickel, its resistance value "Is 9 ohms per square. This is the rod of action exposed to a layer-dissolving bath of 1N hydrochloric acid, through which air is passed for 60 minutes} the resistance value then bx3 increased to 750 ohms per square.

Example III

By following the procedure described in Example I, a stick is made with coated with a layer of phosphorus-containing nickel3, its resistance value 'Jj ^ ohms per square. After an hour of treatment this rod - with a solution of 1/3 raol. Phosphoric acid, by which When air is blown, the resistance value was up to 2000 ohms per square increased.

Example IV

A dtab is in the manner described in Example I with a Provide a layer of phophorhtiltifjen wraps, the Vuder3tandswert 18 0hm teträ't. This rod vviri the action of a layer loosening, air j archf exposed water baths. It's twelve hours '' The average value increased to 520 ohms, after 18 years to 2400 ohms

2C after 'Δ- hours to ' -y) Q0 ohms and after 22 hours to 44.OCO ohms.

In the process of dissolving in acid through which air is blown, i, ic. \ Cicia ioaen in water more slowly, and the flattening begins with an inner layer.

909844/1649. bad ORIGINAL

Claims (2)

^ HK. 1292 PATEMENT CLAIMS 4 1. Process for the production of very thin Metallschichtcn on a electrically non-conductive material such as Xeraisik, glass, Kuna tatoff, on <te chemically deposited a thin layer of phosphorus-containing nickel is characterized in that the objects of action exposed to diluted, aerated acid or water The loosening of the metal layer subsides after a certain time. 2. Objects made of electrically non-conductive material with a very thin jet of phosphorus] ·; Nickel obtained by the process of claim 1. 9098AA / 1 6A9 ⁸ ^ original