Skip to main content

LATEST POST

MATHS TALENT TEST SCORES RELEASED OVERALLS

Post a Comment

ABOUT CORROSION

CORROSION




It is defined as the chemical or electrochemical attack of metals by the environment.

the effects of corrosion by these factors;


  • humidity
  • temperature
  • purity of  metal
  • the physical state of metal
  • nature of ions present in it
  • PH
  • position in electrochemical series
  • relative areas of anode and cathode

electrochemical theory of corrosion;


this theory depends on its electrode potential of metal(anode).if a high electrode metal comes in contact with the low electrode(cathode) potential metal causes the galvanic cell setup.

note: the large corrosion occurs at anodic metal.

the galvanic cells are three types:


composition cell;

in this, both the zinc and copper electrodes are dipped in the same electrolysis solution. 
here the zinc is act as anode and the copper is act as like cathode.the electrons are transferred from anode to cathode.here the anode gets corroded.

stress cell;

These types of cells formed by the drawing, rolling, welding, heat treatment of metals.
stressed areas at the metal act as like an anode causes corrosion.

concentration cell;

this type of cells formed the differential oxygen concentration.poor oxygenated parts act like anodes and causes the corrosion.

RUSTING OF IRON:


  • (Fe2O3xH2O)
  • corrosion of iron is called rusting.

prevention methods for avoiding:

  • using metal high purity
  • alloying
  • protective coating by the metallic or non-metallic or organic.

READ THIS ARTICALES

GSM GLOBAL SERVICE FOR MOBILE COMMUNICATION

GSM IS NOTHING BUT GLOBAL SYSTEM FOR MOBILE COMMUNICATION. GSM SIM 800A: HIGHLY MODERN GSM.MOST POPULAR AND ADVANCED GSM CONNECTION BETWEEN GSM AND ARDUINO: WHENEVER WE WANT TO CONNECT THE GSM TO ARDUINO IS QUITE SIMPLE WHY BECAUSE WE HAVE TO MADE ONLY THREE CONNECTIONS. THEY ARE:[TX AND RX AND GROUND] GSM IS AN INTERNATION STANDARD; THERE ARE SEVERAL GSM MODULUS SIM900,SIM 800A,SIM 808,GSM 520 etc, also, there are several subcategories in the above modules. NOTE: the sim 800A can send or receive data over GPRS, send or receive SMS, and voice calls. it can communicate with pc or microcontroller. AT commands are the main communication commands to all gsm modules. AT means attention commands. specifications of gsm 800a: it operates on quad-band 850/1900 MHz. weight around 40grams. current must be more than 1 ampere. supply voltage range 5v-20v. it can hold the sim card. two LEDs are used in it, one is for network led and the other is for ring led. the above-mentioned specifications are s...
Post a Comment
Read more

THE INVENTIONS OF SCIENTISTS AND THE PHYSICAL QUANTITES

 Ok guys, these are the inventions and scientific names which changes the world like this:  tuning Fork invented by the conig. The sound was recorded and reproduced for the first time by Edison next. The first law of thermodynamics was introduced by the Joul. Weber scientists introduced the molecular theory of magnetism. And this theory of magnetism improved by the eving. Scientists coulomb invented the law of magnetic forces. Bennett invented the gold-leaf electroscope. Michael Faraday introduced electrolysis. The first theory of Hanson oerested is invented by a wire carrying current behaves like a magnet. E Goldstein proposed the positive rays. JJ Thomson proposed the cathode rays. Proton was discovered by  Rutherford. Neutron was discovered by James Chadwick. Discovery of electrons by millicon. X-rays  invented by rontgen. Artificial radioactivity was discovered by Joliot and iren curie. Artificial transmutation was introduced by Rutherford. Nuclear fission ...
2 comments
Read more