CN1048080A - Automobile cold start is with the preparation method of PTC material and element - Google Patents

Abstract

The invention belongs to the preparation method of inorganic functional material and element thereof.The manufacture method that the purpose of invention is to provide automobile cold start to use ptc material is in the hope of substituting existing imported auto cold starter.Major technique feature of the present invention is the synthetic earlier BaTiO that contains certain donor impurity ₃And PbTiO ₃Base-material is then with certain proportion and adding small amounts of additives and Al ₂O ₃, BaCO ₃, SiO ₂, TiO ₂And MnCl ₂4H ₂O, then by general ceramic process moulding, sintering in airtight aluminium oxide crucible, firing temperature are 1250-1300 ℃ of insulation 45-15 minute.

Description

Automobile cold start is with the preparation method of PTC material and element

The invention belongs to the preparation method of inorganic functional material and element thereof.

Positive temperature coefficient (PTC) material is that a class is with BaTiO ₃Be the semiconductive ceramic of base, it is by at BaTiO ₃And with BaTiO ₃Mix a certain amount of donor impurity in the solid solution for base, the material that sintering forms in oxidizing atmosphere.Under the room temperature, it shows n n doped semiconductor feature.Along with the rising of temperature, more than a certain specific temperature (Curie temperature of material or phase change transition temperature), specific resistance sharply increases, and its amplitude can reach several magnitude, so-called PTC effect that Here it is.Utilize the specific resistance of this material to vary with temperature characteristic, can make temperature transducer, delay device and controlled heating element all can be widely used aspect electronic device, automotive industry, chemical, health care, industrial automation and the household electric appliance.

The ptc material that automobile cold start is used is based on automobile under the weather of cold, exist starting difficulty, and gasoline enters vaporizing chamber without preheating also can to produce gasoline combustion incomplete during cold conditions, causes waste of fuel, blowdown is serious and machine problem such as part wearing and tearing increase in addition.For solving this a series of problems, developed multiple cold device abroad, wherein regarded as the most promising cold starting device by automobile industry as the manifold heater of heating element with ptc material.The Shanghai Santana Car of domestic introduction, Beijing jeep 213 all are equipped with this device.Regrettably the ptc material no matter domestic and foreign literature is delivered is used on automobile, perhaps in the data of introduction of production line, narrate the structure of cold starting heater only morely, characteristics between each constituent element and to the chemical composition and the preparation process of its material say nothing (for example, U.S.P 4419564).And the interrelated data of ptc material, for example people " Grain; Bondary Resistance in Semicondncting Barium titanate " such as R.N.Basu (IEEE Vol No p.685,1986) and people " preparation of high-curie-point Barium-Lead-Titanate and their PTCR Characteristics " (Amer such as K.Kuwabara, Ceram, Soc, Bull, 64(10) 1194-98,1985) the related regular content of materials science is discussed all morely, and the proprietary material of automobile cold start and the manufacture method of element are reported very few.

The object of the present invention is to provide the automobile cold start manufacture method of ptc material and element, cold the device heater element of using in the hope of car Santana and Beijing 213 jeep production lines of the introduction of alternative Shanghai also improves the cold-start performance that has domestic automobile now.

Specifically, the objective of the invention is to realize by following several respects:

(1) proposed a whole set of preparation process, can produce Curie temperature according to this is 180 ℃, and room temperature resistivity is 20～70 Ω cm, and sudden change reaches 10 near Curie temperature ³～10 ⁴Ptc material;

(2) the PTC element made from ptc material provided by the invention; Boundary dimension Φ 21X1mm, after two interareas imposed Ohm contact electrode, its room temperature resistance (25 ℃) was 0.8-2.0 Ω, can satisfy the requirement of cold device of automobile;

The present invention prepares ptc material and PTC element by technological process shown in Figure 1, and 1 to 5 is respectively the synthetic BaTiO that is added with a certain amount of donor impurity among the figure ₃The base-material manufacturing process is respectively that batching (weighing), ball milling are mixed, oven dry is sieved, synthetic under briquetting and the uniform temperature.

Among the figure 1 ' to 5 ' be the synthetic PbTiO that is added with a certain amount of donor impurity ₃The base-material manufacturing process is respectively that batching (weighing), ball milling are mixed, oven dry is sieved, synthetic under briquetting and the uniform temperature.

6 are weighing proportioning PTC powder technology, will contain the PbTiO of a certain amount of donor impurity ₃With the BaTiO that contains a certain amount of donor impurity ₃Powder mixes by 14: 0.86 mole ratios, and adds Al ₂O ₃, SiO ₂, BaCO ₃, TiO ₂In at least two kinds of impurity and MnCl ₂4H ₂O.

7 are ball milling mixing pulverizing; 8 are oven dry and adding Bond; 9 for pulverizing after the precompressed again; 10 is the certain pressure compacted under; 11 get rid of Bond; Burn till under 12 uniform temperatures; 13 are processed into required boundary dimension; 14 chemical nickel platings; 15 burning infiltration low-temperature silvers slurry; 16 test performances.

Be specifically described as follows:

(1) main material BaCO ₃Chemical pure (content 〉=99%)

Pb ₃O ₄Technical pure (PbO content 〉=97.0%)

TiO ₂Technical pure (enamel level, content 〉=99%)

(2) donor impurity: Nb ₂O ₅Chemical pure (content 〉=99%)

La ₂O ₃″ ″ ″

Y ₂O ₃″ ″ ″

Sb ₂O ₃″ ″ ″

Get a kind of in above-mentioned four kinds of donor impurities or two kinds, total addition level is 0.1～0.3(mol) %.

(3) other affix and adding quantity

Affix purity adding quantity (wt%)

Al ₂O ₃Chemical pure (content 〉=99%) 0.72～1.67mol%

BaCO ₃″ 0.615～1.30mol%

SiO ₂″ 2.02～4.04mol%

TiO ₂Technical pure (enamel level, content 〉=99%) 2.1～4.5mol%

MnCl ₂·4H ₂O 0.01～0.030mol%

Remove MnCl ₂4H ₂Outside the O, get in the above-mentioned affix at least two kinds.

(4) sintering is to carry out in airtight aluminium oxide crucible, and concrete technology is:

Room temperature to 1150 ℃ speed is 300～400 ℃/hour

1150～1200 ℃ are incubated half an hour

And then be raised to 1250 ℃ to 1300 ℃, with 600～1200 ℃/hour, speed was rapidly heated general 5～15 minutes.

1250～1300 ℃ of scopes are incubated 10～45 minutes

Then, 1000 ℃ of cooling rates of 1250 ℃～1300 ℃ coolings be 500-600 ℃/hour 1000 ℃-→ room temperature closes the stove natural cooling

The invention has the advantages that

(1) the parent material grade of preparation ptc material provided by the invention is low, particularly TiO ₂And Pb ₃O ₄Be technical grade, help producing in batches, reduce cost;

(2) it is stable that the chemical composition of the material of Ti Chuing and affix make the material property of preparation, and process parameter is easy to control;

(3) firing range broad (about 20 ℃), and in this wide temperature range, the microstructure of material and electrical property all can be controlled preferably, satisfy of the requirement of cold device to material and element;

(4) go up utmost point technology and not only guarantee the Ohmic contact face but also good conductive is arranged and corrosion resistance characteristic, and the bonding when being easy to the device assembling.

As embodiments of the invention one be:

Get doping 0.15(mol) %Sb ₂O ₃BaTiO ₃(consist of BaTi _1.01O ₃+ 0.15(mol) %Sb ₂O ₃Note is made Ba(Sb) TiO ₃) and doping 0.15(mol) %.Sb ₂O ₃And 1.0wt%Pb ₂O ₃PbTiO ₃(consist of PbTiO ₃+ 0.15(mol) %Sb ₂O ₃+ 1.0wt%PbO note is made Pb(Sb) TiO ₃), by the manufacturing process of example among Fig. 15 and 1 ' to 5 ' provided, by the synthetic BaTiO that contains certain donor impurity of general ceramic process ₃Base-material and PbTiO ₃Base-material, BaTi _1.01O ₃+ 0.15(mol) %Sb ₂O ₃Synthesis temperature is 1150 ℃ of insulations 4 hours; PbTiO ₃+ 0.15(mol) %Sb ₂O ₃Synthesis temperature be 700 ℃ 1 hour, 950 ℃ 2 hours.

By following proportioning, be made into the PTC powder then:

Ba（Sb）TiO ₃0.86（mol）

Pb（Sb）TiO ₃0.14（mol）

Al ₂O ₃1.17（mol%）

SiO ₂2.64（mol%）

＊MnCl ₂·4H ₂O 0.024（mol%）

(* MnCl ₂4H ₂O gets liquor capacity to add it in proportion in the alcohol that is dissolved in earlier more than 95%).

Getting the 5wt% poly-vinyl alcohol solution is Bond, adds the 6ml Bond by every 100g powder, and precompression is 1000kg/cm ², getting rid of binder temperature is 800 ℃/hr, then test piece is placed pure Al ₂O ₃Airtight sintering in the crucible is used ZrO between test piece ₂Powder separates, and is raised to 1180 ℃ with 300-400 ℃/hr speed, is incubated 30 minutes, and the rapid rate with 15 ℃ of per minutes is raised to 1260 ℃ then, is incubated 15～20 minutes, cools to 1000 ℃ with 500 ℃/hr speed again, closes the stove natural cooling.

The performance of gained material is as follows: Tc～180 ℃

ρ _v（RT）～30～50Ω·cm

△ρ _v（ρ _vmax/ρvmin）≥10 ³

Embodiment 2

Get BaTi _1.01O ₃+ 0.075mol%La ₂O ₃+ 0.075mol%Nb ₂O ₅

PbTi _1.01O ₃+0.075mol%La ₂O ₃+0.075mol%Nb ₂O ₅+1.0wt%PbO

Be made into base-material, wherein La ₂O ₃Should 900 ℃ of calcinings of first high temperature during weighing be cooled to and take by weighing after exsiccator is put in 200 ℃ of taking-ups.

Be made into ptc material in following ratio then

Ba（La）Ti（Nb）O ₃0.80mol%

Pb（La）Ti（Nb）O ₃0.14mol%

Al ₂O ₃1.43mol%

SiO ₂2.95mol%

TiO ₂3.95mol%

MnCl ₂·4H ₂O 0.012mol%

All the other technologies are with embodiment 1.

Gained ptc material performance is: Tc～180 ℃

ρ _v（RT）～40～60Ω·cm

△ρ _v（ρ _vmax/ρ _vmin）≥10 ³

Claims (5)

1, a kind of automobile cold start comprises the powder preparation with the preparation method of PTC material and element, and ball mill mixing, forming and sintering, processing, chemical nickel plating and roasting silver is characterized in that:

(1) the synthetic BaTiO that contains a certain amount of donor impurity ₃Base-material and PbTiO ₃Base-material;

(2) with BaTiO ₃Base-material and PbTiO ₃Base-material mixes and interpolation small amount of impurities and MnCl ₂4H ₂O makes the PTC powder;

(3) will be behind the PTC powder ball milling mixing oven dry add Bond, after the moulding in airtight aluminium oxide crucible sintering, sintering temperature is 1250～1300 ℃, is incubated 10～45 minutes.

2, by the described preparation method of claim 1, it is characterized in that described BaTiO ₃Affix as donor impurity in the base-material is Nb ₂O ₅, La ₂O ₃, Y ₂O ₃And Sb ₂O ₃In a kind of or two kinds, total addition level is 0.1～0.3 mole %.

3, by the described preparation method of claim 1, it is characterized in that described PbTiO ₃Affix as donor impurity in the base-material is Nb ₂O ₅, La ₂O ₃, Y ₂O ₃And Sb ₂O ₃In a kind of or two kinds, total addition level is 0.1～0.3 mole %.

4, by claim 1,2 or 3 described preparation methods, it is characterized in that and to contain the BaTiO of a certain amount of donor impurity ₃And PbTiO ₃Mixed by 0.86: 0.14 mole ratio, and add Al ₂O ₃, BaCO ₃, SiO ₂, TiO ₂And MnCl ₂4H ₂O removes MnCl ₂4H ₂Outside the O, get in the above-mentioned affix at least two kinds, their adding quantity is respectively 0.30-0.70,0.50-1.00,0.50-1.00,0.70-1.50(are weight %).

5,, it is characterized in that it is that room temperature to 1150 ℃ speed is 300-400 ℃/hour that described sintering heats up by the described preparation method of claim 4

1150 ℃～1200 ℃ are incubated half an hour

Be raised to 1250 ℃～1300 ℃ insulations 10～45 minutes fast with 600-1200 ℃/speed at one hour rating then,

1250 ℃ then～1300 ℃ cool to 1000 ℃, and cooling rate is 500-600 ℃/hour, 1000 ℃-room temperature, close the stove cooling.

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